방문 예정자 목록 및 방문 일정:

november 2024

01aprallday31marJinhyoung LeeSungkyunkwan University (SKKU)(All Day) KST

01sepallday31augYou-Shin NoKonkuk University(All Day) KST

18novallday20Ulrich HöferPhilipps-University Marburg & University of Regensburg(All Day) KST

20novalldayJae-Pil SoSoongsil University(All Day: wednesday) KST

21novalldayIgor AharonovichUniversity of Technology Sydney(All Day: thursday) KST

21novalldayKarolina SłowikNicolaus Copernicus University(All Day: thursday) KST

22novalldayJehyung KimUlsan National Institute of Science & Technology (UNIST)(All Day: friday) KST

26novalldayEunmi ChaeKorea University(All Day: tuesday) KST

Past Research Stays and Visits:

october 2024

31octalldayHuijun HanUlsan National Institute of Science & Technology (UNIST)(All Day: thursday) KST

24octalldayRohit Kishan RayIBS Center for Theoretical Physics of Complex Systems(All Day: thursday) KST

11octalldayNiccolò FontanaUniversity of Oxford(All Day: friday) KST

08octalldayYoungwook ParkFritz Haber Institute of the Max Planck Society(All Day: tuesday) KST

01sepallday31augYou-Shin NoKonkuk University(All Day) KST

01augallday16octNikita KomarovUNSW Sydney(All Day) KST

22julallday18octYasuo YoshidaKanazawa University(All Day) KST

22julallday18octMasahiro HazeThe Institute for Solid State Physics, The University of Tokyo(All Day) KST

01aprallday31marJinhyoung LeeSungkyunkwan University (SKKU)(All Day) KST

september 2024

12sepalldayPham Thi HueUniversity of Ulsan(All Day: thursday) KST

06sepalldayLewis AntillUniversity of Oxford(All Day: friday) KST

05sepalldayDenis JankovicIPCMS (University of Strasbourg/CNRS)(All Day: thursday) KST

28augallday13sepMario RubenKarlsruher Institut für Technologie (KIT)(All Day) KST

04junallday06sepLily WattThe University of British Columbia(All Day) KST

august 2024

28augalldayMasahiro YamashitaTohoku University(All Day: wednesday) KST

20augalldaySungkun HongUniversity of Stuttgart(All Day: tuesday) KST

19augallday20Muskan SandeSungkyunkwan University(All Day) KST

05augallday06Johannes BarthTUM School of Natural Sciences(All Day) KST

22julallday24augHiroki MaekawaKanazawa University(All Day) KST

july 2024

05julalldayJu Young KimDelegation of the European Union to the Republic of Korea & European Commission(All Day: friday) KST

05julalldayAnett SchwarzEmbassy of the Federal Republic of Germany Seoul(All Day: friday) KST

05julalldayAlessandra ApicellaHead of Science and Technology Office in the Embassy of Switzerland(All Day: friday) KST

03junallday02julSimeon BodeUniversity of Göttingen(All Day) KST

june 2024

26junalldaySergey UchaikinIBS Center for Axion and Precision Physics Research(All Day: wednesday) KST

24junalldaySven RoggeUniversity of New South Wales(All Day: monday) KST

17junallday23Talal MallahUniversité Paris-Saclay(All Day) KST

13junalldayUngdon HamKorea Research Institute of Standards and Science (KRISS)(All Day: thursday) KST

13junalldayIn-Ho LeeKorea Research Institute of Standards and Science (KRISS)(All Day: thursday) KST

10junalldayMichael FlattéThe University of Iowa(All Day: monday) KST

10junalldayGiulia GalliThe University of Chicago(All Day: monday) KST

07junalldayAndrew ClelandThe University of Chicago(All Day: friday) KST

may 2024

24mayalldayCentre national de la recherche scientifique (CNRS)Centre national de la recherche scientifique (CNRS)(All Day: friday) KST

21mayalldayChristian SchönenbergerUniversität Basel(All Day: tuesday) KST

07mayallday08Markus AspelmeyerUniversity of Vienna(All Day) KST

april 2024

30apralldayJoong Il ChoiCenter for Nanomaterials and Chemical Reactions, IBS(All Day: tuesday) KST

17aprallday18Stefan TautzForschungszentrum Jülich(All Day) KST

17apralldayJe-Geun ParkSeoul National University(All Day: wednesday) KST

11apralldayWangkook Kim & Engineering TeamGwangju Institute of Science and Technology (GIST)(All Day: thursday) KST

11apralldayJina Hwang & groupSungshin Women’s University(All Day: thursday) KST

02apralldaySébastien CodinaEmbassy of France(All Day: tuesday) KST

19feballday12aprHalis YarimTechnische Universität Berlin(All Day) KST

march 2024

07marallday08Takashi KumagaiInstitute for Molecular Science (Japan)(All Day) KST

february 2024

29feballdayMyungchul OhPOSTECH (Pohang University of Science and Technology)(All Day: thursday) KST

21feballday22Jinwon LeeDelft University of Technology (TU Delft)(All Day) KST

01feballdayLuke OtienoKyungpook National University(All Day: thursday) KST

january 2024

24janallday28Christian R. AstMax Planck Institute for Solid State Research(All Day) KST

24janallday27Berthold JäckHong Kong University of Science and Technology (HKUST)(All Day) KST

21janallday29Magdalena GrzeszczykNational University of Singapore(All Day) KST

11janalldayKyoung-Whan KimKorea Institute of Science and Technology (KIST)(All Day: thursday) KST

08janallday13Harald BruneEcole Polytechnique Fédérale de Lausanne (EPFL), Switzerland(All Day) KST

01janallday29Hoang Anh LeKorea University(All Day) KST

19novallday21janDeung-Jang (DJ) ChoiMaterials Physics Center (CFM-CSIC/UPV), San Sebastián, Spain.(All Day) KST

december 2023

03decallday06Yukio HasegawaThe Institute for Solid State Physics, University of Tokyo(All Day) KST

26novallday01decPaul ThomasUNSW Sydney(All Day) KST

06novallday31decPierre JosseUniversity of Angers(All Day) KST

01novallday31decYining HuFudan University, Shanghai(All Day) KST

02augallday10decWenchao ZhaoTechnische Universität München (TUM)(All Day) KST

november 2023

17novalldayGabriel AeppliETHZ, EPFL, PSI (Switzerland)(All Day: friday) KST

02novallday30Karl-Heinz ErnstEmpa, Swiss Federal Laboratories for Materials Science and Technology(All Day) KST

02novalldayYou-Shin NoKonkuk University, Seoul(All Day: thursday) KST

08octallday12novTaner EsatForschungszentrum Jülich, Peter Grünberg Institute(All Day) KST

31augallday12novAndrés Pinar SoléInstitute of Physics of the Czech Academy of Sciences (FZU)(All Day) KST

october 2023

26octalldayUwe R. FischerSeoul National University(All Day: thursday) KST

22octallday31Lucas SchneiderUniversity of California, Berkeley(All Day) KST

10octallday18Lisanne SelliesUniversität Regensburg(All Day) KST

10octallday13Junho SuhPohang University of Science and Technology(All Day) KST

10octallday13Ania Bleszynski JayichUniversity of California, Santa Barbara(All Day) KST

09octallday19Nicolaj BetzLoth Group, University of Stuttgart(All Day) KST

09octallday15Guido BurkardUniversität Konstanz, Germany(All Day) KST

09octallday12Seigo TaruchaRIKEN Center for Emergent Matter Science(All Day) KST

09octallday13Yasuo YoshidaKanazawa University(All Day) KST

09octallday13Erlina Tik ManKanazawa University(All Day) KST

09octallday13Ying JiangPeking University(All Day) KST

09octallday13Harry Laurence AndersonUniversity of Oxford UK(All Day) KST

08octallday12Andrea MorelloUniversity of New South Wales(All Day) KST

08octallday14Roberta SessoliUniversità degli Studi di Firenze(All Day) KST

08octallday14Mark HoggUniversity of Basel(All Day) KST

08octallday14Danna FreedmanMassachusetts Institute of Technology(All Day) KST

08octallday12Rupert HuberUniversity of Regensburg (UR), Germany(All Day) KST

06octalldayChi ChenAcademia Sinica, Taiwan(All Day: friday) KST

18sepallday14octSufyan ShehadaForschungszentrum Jülich and RWTH Aachen University(All Day) KST

01sepallday14octWolf-Dieter SchneiderEcole Polytechnique Fédérale de Lausanne (EPFL), Switzerland(All Day) KST

07augallday28octSvenja NerreterUniversity of Regensburg, Germany(All Day) KST

september 2023

23sepallday28Hans-Joachim FreundFritz Haber Institute of the Max Planck Society(All Day) KST

23sepallday28Don EiglerIBM Almaden Research Center (Retired)(All Day) KST

04sepallday05Rudolf HaindlMax Planck Institute for Multidisciplinary Sciences(All Day) KST

04sepallday05John H. GaidaMax Planck Institute for Multidisciplinary Sciences(All Day) KST

18augallday14sepJan MartinekInstitute of Molecular Physics (Poland)(All Day) KST

18augallday02sepArzhang ArdavanUniversity of Oxford(All Day) KST

august 2023

26augallday27Alessandro ToschiInstitute of Solid State Physics (Technische Universität Wien)(All Day) KST

26augallday27Giorgio SangiovanniUniversity of Würzburg(All Day) KST

25augallday26Pascal RuffieuxSwiss Federal Laboratories for Materials Science and Technology(All Day) KST

18augalldayAndreas OsterwalderEcole Polytechnique Federale de Lausanne (EPFL)(All Day: friday) KST

17aug2:00 pm8:00 pmYousoo KimThe University of Tokyo2:00 pm - 8:00 pm KST

15augallday19Wilson HoUniversity of California Irvine(All Day) (KST) Center for Quantum Nanoscience

10augallday14Alec WodtkeMax Planck Institute for Multidisciplinary Sciences(All Day) KST

07aug11:00 am12:00 pmClaudiu GenesMax Planck Institute for the Science of Light11:00 am - 12:00 pm KST

25julallday31augNicolas LorenteMaterials Physics Center (CFM-CSIC/UPV), San Sebastián, Spain.(All Day) KST

22mayallday22augAngéline LafleurUniversity of Ottawa(All Day) KST

july 2023

21julalldayDaniël StuartEindhoven University of Technology (Netherlands)(All Day: friday) KST

20julalldayDuck-Ho KimKorea Institute of Science and Technology (KIST)(All Day: thursday) KST

14julalldayHayley WallenNature Reviews Methods Primers, Springer Nature(All Day: friday) KST

14julalldayWoo-Joong KimSeattle University(All Day: friday) KST

08junallday13julMarco WeissUniversity of Regensburg, Germany(All Day) KST

15mayallday01julJiwon ChoiNational University of Singapore (NUS)(All Day) KST

07mayallday30julRik BroekhovenDelft University of Technology(All Day) KST

june 2023

22junalldaySungkyun ChoiCenter for Integrated Nanostructure Physics IBS, SungKyunKwan University(All Day: thursday) KST

Event Details

Sungkyun Choi

Affiliation: Center for Integrated Nanostructure Physics IBS, SungKyunKwan University

Research interests: Quantum Spin Liquids, Multiferroics, Topology in Magnetism, Quantum Phase Transitions

Time

All Day (Thursday)

Calendar GoogleCal

20jun11:00 am12:00 pmPierre JosseUniversity of Angers, Yonsei University11:00 am - 12:00 pm KST

16jun11:00 am12:00 pmVasily KravtsovITMO University11:00 am - 12:00 pm KST

16jun10:00 am3:00 pmVasily KravtsovITMO University10:00 am - 3:00 pm KST

08jun9:00 am7:00 pmPaul WeissUniversity of California, Los Angeles, USA9:00 am - 7:00 pm KST

07jun12:00 pm4:00 pmDaejin EomKorea Research Institute of Standards and Science12:00 pm - 4:00 pm KST

05jun(jun 5)12:00 pm06(jun 6)2:00 pmSanghoon KimUniversity of Ulsan12:00 pm - 2:00 pm (6) KST

05jun12:00 pm7:00 pmYoung Jae SongSungkyunkwan University SKKU Advanced Institute of Nanotechnology (SAINT)12:00 pm - 7:00 pm KST

02jun2:00 pm3:00 pmKyoung-Duck ParkPohang University of Science and Technology (POSTECH)2:00 pm - 3:00 pm KST

28mayallday09junRuslan TemirovPeter Grunberg Institute, Forschungszentrum Jülich(All Day) KST

22mayallday06junValentin MaissenPeter Grunberg Institute, Forschungszentrum Jülich(All Day) KST

may 2023

20feballday09mayFranziska RüttgerUniversity of Göttingen(All Day) KST

01feballday31mayGeorg TraegerUniversity of Gottingen(All Day) KST

10janallday06mayMireia Tena ZuazolacigorragaCentro de Fisica de Materiales(All Day) KST

08janallday01mayDeung Jang ChoiCentro de Fisica de Materiales(All Day) KST

april 2023

18aprallday27Sebastian LothUniversity of Stuttgart(All Day) KST

18aprallday25Kirsten von BergmannUniversität Hamburg(All Day) KST

18aprallday25Matthias BodeUniversity of Würzburg(All Day) KST

17apralldayKatja BeckerDFG, German Research Foundation(All Day: monday) KST

14apralldayMaki KawaiInstitute for Molecular Science, National Institutes of Natural Sciences (NINS) (All Day: friday) KST

09aprallday15Laëtitia FarinacciFreie Universität Berlin(All Day) KST

15novallday30aprMichele CapraPolitecnico di Milano(All Day) KST

march 2023

31mar2:00 pm3:30 pmMaria SpethmannUniversity of Basel2:00 pm - 3:30 pm KST

08janallday11marNicolas LorenteCentro de Fisica de Materiales(All Day) KST

february 2023

09feb10:00 am11:30 amDaniel Kyungdeock ParkYonsei University10:00 am - 11:30 am KST

02feb1:30 pm3:00 pmJoseph A StroscioNational Institute of Standards and Technology1:30 pm - 3:00 pm KST

01feballday28Eric SwitzerUniversity of Central Florida(All Day) KST

december 2022

14dec1:30 pm3:00 pmClément CabanetosUniversity of Angers1:30 pm - 3:00 pm KST

Event Details

Clément Cabanetos

Academic Affiliation: University of Angers

Title: “Sooner or later, everything old is new again”: Functionalization and use of a forgotten dye

Abstract:

Abstract: Since the advent of organic electronics, various classes of π-conjugated molecular and macromolecular semiconductors have been reported. Among them, imide-containing rylenes have attracted considerable research attention due to their redox, electron-withdrawing and charge-carrier transport properties, as well as their excellent chemical, thermal, and photochemical stabilities. Naphthalene diimide (NDI) and perylene diimide (PDI) can be unequivocally recognized as the most studied imide based building blocks for the preparation of high-performance electron transporting optoelectronic materials. Within these wide-ranging studies, considerable effort has been undertaken to functionalize both the bay positions and the nitrogen atom constituting the imide group (N-positions) to bring solubility, tune the molecular (opto)electronic characteristics, and build extended π-conjugated architectures. Despite interesting fluorescent properties, the N-(alkyl)benzothioxanthene-3,4-dicarboximide (BTI), a sulfur containing rylene-imide dye, has not yet triggered such interest. Exclusively functionalized on the N-position for imaging and staining applications, we recently focused our attention in functionalizing the p-conjugated core of this forgotten dye for the preparation of new and original materials for organic electronics, but not only…

Clément Cabanetos: clement.cabanetos@cnrs.fr

After graduation in 2008, Clément Cabanetos undertook a PhD at the CEISAM laboratory (Nantes, France) on the synthesis of new crosslinkable polymers for nonlinear optical applications. Shortly after his thesis defense, he joined the group of Jean Fréchet (KAUST, (Saudi Arabia) as a postdoctoral fellow to prepare efficient π-conjugated macromolecular materials for organic photovoltaics. In 2013, he was recruited as a permanent CNRS researcher and joined the MOLTECH-Anjou laboratory in Angers to develop new and original concepts for organic electronics. He then defended his habilitation in 2018 (associate professorship) and received in 2019 the CNRS bronze medal that awards young and promising researchers. Recently (august 2021) he moved to Seoul in a joint French (CNRS)-Korean International laboratory (2BFUEL) hosted by the Yonsei University where he was promoted director in September 2022.

Time

(Wednesday) 1:30 pm - 3:00 pm

Calendar GoogleCal

05decallday10Alexina OllierUniversity of Basel(All Day) KST

04decallday06Pavel JelinekInstitute of Physics of the Czech Academy of Sciences (FZU)(All Day) KST

november 2022

16novallday22Vibhuti Narayan RaiKarlsruhe Institute of Technology(All Day) KST

01nov3:00 pm4:00 pmHan-woong YeomCALDES, IBS & POSTECH3:00 pm - 4:00 pm KST

Event Details

Han-woong Yeom

Academic Affiliation: CALDES, IBS & POSTECH

Title: Nano-tsunami along atomic chains and domain walls for robust informatics

Abstract:

Storing and manipulating information in robust and dissipationless ways is of prime interest in various fields of science and technology. Using topologically protected local excitations, form examples, skyrmions and Majorana fermions, such robust informatics may be realized. This talk reviews our own approach to this issue, which deals with new types of solitons in electronic systems. We will first discuss atomic chains formed on silicon surfaces in charge-density-wave ground states and their solitons. We recently identified individual electronic solitons in indium atomic chains on a Si(111) surface and, more recently, in silicon chains on stepped silicon surfaces . Due to their unique structures, they represent unprecedented topological systems of Z₄ [1] and Z₃ [2], respectively, with three and two distinct solitons. These solitons can store, deliver, and operate multi-level information bits, which are protected topologically [3]. We further demonstrate solitons with higher multiplicity can be formed as a form of mobile kinks [4] along the charge-density-wave domain walls on a 2D material of 1T-TaS₂[5]. Thus, the possibility of multi-level and topologically protected information processing with solitons, or solitonics, is well demonstrated. Further studies on soliton-defect, soliton-soliton, and soliton-excitation interactions are exciting for soliton applications.

References:

[1] S. M. Cheon, S. H. Lee, T. H. Kim, and H. W. Yeom, Science 350, 182 (2015).

[2] J. W. Park, E. Do, J. S. Shin, S. K. Song, O. P. Jelinek, and H. W. Yeom, Nature Nanotechnology 17, 244 (2022).

[3] S. M. Cheon, T. H. Kim, and H. W. Yeom, Nature Physics 13, 444 (2017).

[4] J. W. Lee, J. W. Park, and H. W. Yeom, PRL, under review (2022).

[5] D. Cho, G. Gye, J. Lee, S. H. Lee, L. Wnag, S-W. Cheong, and H. W. Yeom, Nature Commun. 8, 392 (2017)

Han Woong Yeom^1,2

¹Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science, Pohang 37673, Korea.

²Department of Physics, POSTECH, Pohang 37673, Korea.

Time

(Tuesday) 3:00 pm - 4:00 pm

Calendar GoogleCal

01novallday30Leonard EdensCIC nanoGUNE(All Day) KST

23octallday19novWolf-Dieter SchneiderEcole Polytechnique Fédérale de Lausanne (EPFL), Switzerland(All Day) KST

october 2022

17oct5:00 pm6:00 pmColloquium: Jeremy LevyUniversity of Pittsburgh5:00 pm - 6:00 pm (KST) Center for Quantum Nanoscience

15octallday22Jeremy LevyUniversity of Pittsburgh(All Day) (KST) Center for Quantum Nanoscience

04octallday15Ashley Jiwon ShinUniversity of California, Los Angeles, USA(All Day) KST

september 2022

26sepalldayAdam KollinRHK Technology, Inc.(All Day: monday) KST

august 2022

18aug4:00 pm5:00 pmJingcheng LiSun Yat-sen University4:00 pm - 5:00 pm KST

16augalldayYoungchan KimUniversity of Surrey(All Day: tuesday) KST

15augallday16Yousoo KimUniversity of Tokyo(All Day) KST

23julallday12augJens WiebeUniversity of Hamburg, Germany(All Day) KST

july 2022

20julallday21Arzhang ArdavanUniversity of Oxford(All Day) KST

07julalldayEvent CancelledPaul WeissUniversity of California, Los Angeles, USA(All Day: thursday) KST

28junallday02julMario RubenKIT Karlsruhe, Germany(All Day) KST

28junallday02julDaniel LossUniversity of Basel, Switzerland(All Day) KST

28junallday01julValeria SheinaUniversity Paris-Saclay, France(All Day) KST

june 2022

14junallday18Franz Josef GiessiblUniversity of Regensburg, Germany(All Day) KST

02junallday24William KollOhio State University, USA(All Day) KST

may 2022

27may10:15 am11:15 amHosung SeoAjou University10:15 am - 11:15 am KST Jupiter Meeting Room

Event Details

Hosung Seo

Academic Affiliation: Ajou University

Date and Time of the Talk: May 27th, 2022; 10:15 – 11:15

First-principles theory of extending the spin qubit coherence time in hexagonal boron nitride

Negatively charged boron vacancies (VB–) in hexagonal boron nitride (h-BN) are a rapidly developing qubit platform in two-dimensional materials for solid-state quantum applications. However, their spin coherence time (T2) is very short, limited to a few microseconds owing to the inherently dense nuclear spin bath of the h-BN host. As the coherence time is one of the most fundamental properties of spin qubits, the short T2 time of VB– could significantly limit its potential as a promising spin qubit candidate. In this study, we theoretically proposed two materials engineering methods, which can substantially extend the T2 time of the VB– spin by four times more than its intrinsic T2. We performed quantum many-body computations by combining density functional theory and cluster correlation expansion and showed that replacing all the boron atoms in h-BN with the 10B isotope leads to the coherence enhancement of the VB– spin by a factor of three. In addition, the T2 time of the VB– can be enhanced by a factor of 1.3 by inducing a curvature around VB–. Herein, we elucidate that the curvature-induced inhomogeneous strain creates spatially varying quadrupole nuclear interactions, which effectively suppress the nuclear spin flip-flop dynamics in the bath. Importantly, we find that the combination of isotopic enrichment and strain engineering can maximize the VB– T2, yielding 207.2 and 161.9 μs for single- and multi-layer h-10BN, respectively. Furthermore, our results can be applied to any spin qubit in h-BN, strengthening their potential as material platforms to realize high-precision quantum sensors, quantum spin registers, and atomically thin quantum magnets.

[1] A. Gottscholl et al., Nat. Mater. 19, 540-545 (2020)

[2] A. Gottscholl et al., Sci. Adv. 7, eabf3630 (2021).

[3] M. Ye, H. Seo, and G. Galli, npj Comp. Mater. 5, 44 (2019).

Time

(Friday) 10:15 am - 11:15 am KST

Location

Jupiter Meeting Room

B1-61, Research Cooperation Building, 52 Ewhayeodae-gil, Daehyeon-dong

Calendar GoogleCal

15marallday10mayRyo KawaguchiTohoku University, Sendai, Japan(All Day) KST

22sepallday07mayRobbie ElbertseDelft University of Technology, the Netherlands(All Day) KST

april 2022

16marallday15aprFerdous AraTohoku University, Sendai, Japan(All Day) KST

february 2022

20novallday13febDeung-Jang ChoiCSIC, Spain(All Day) KST

20novallday13febNicolas LorenteCSIC and DIPC, Spain(All Day) KST

13novallday24febCristina Mier GonzalezCSIC-UPV/EHU, Spain(All Day) KST

september 2021

03sepalldayMasahiro HazeThe Institute for Solid State Physics, The University of Tokyo(All Day: friday) KST

may 2021

19aprallday21mayMingee ChungSchool of Physics and Astronomy, the University of Birmingham, Birmingham, UK(All Day) KST

march 2021

13marallday22Iyyappa Rajan PaneerAsia Pacific Center for Theoretical Physics(All Day) KST

december 2020

21sepallday31decMasahiro HazeInstitute for Solid State Physics, University of Tokyo(All Day) KST

september 2020

01mayallday30sepDeung-Jang ChoiCentro De Fisica De Materiales, Spain(All Day) KST

august 2020

15julallday31augNicolas LorenteCentro De Fisica De Materiales, Spain(All Day) KST

july 2020

01feballday31julHervé AubinDepartment of Nanoelectronics, CNRS, France(All Day)

february 2020

24feballday28Delegation from Forschungszentrum JülichQuantum Nanoscience Division, Peter Grünberg Institut, Forschungszentrum Jülich(All Day) KST

12feballday13Ali YazdaniPrinceton University, USA(All Day)

09feballday22Markus TernesResearch Center Jülich, Germany(All Day)

january 2020

20jan12:30 pm3:30 pmDelegation of EU Science CounselorsEmbassy of Switzerland in the Republic of Korea12:30 pm - 3:30 pm

19janallday23Koen BastiaansLeiden University, Netherlands(All Day)

december 2019

13dec10:00 am11:00 amKrisztián PalotásWigner Research Center for Physics10:00 am - 11:00 am KST Saturn Seminar Room

Event Details

Krisztián Palotás

Academic Affiliation: Wigner Research Center for Physics, Hungary

Talk: December 13, 2019

First-principles-based simulation of scanning tunneling microscopy: From magnetic surfaces to molecular structures

Understanding and engineering scanning tunneling microscopy (STM) image contrasts is of crucial importance in wide areas of surface science and related technologies, ranging from magnetic surfaces to molecular structures. In the talk different STM tip effects on the image contrast are highlighted based on first principles calculations, going beyond the Tersoff-Hamann model, e.g., within 3D-WKB tunneling theory [1]. Examples include highly oriented pyrolytic graphite [2], which is commonly used for STM calibration, and complex surface magnetic structures exhibiting non-collinear magnetic order, like recently popular topologically protected skyrmions [3]. By comparing STM topographic data between experiment and large scale simulations, a statistical analysis of the tip apex structure is demonstrated for the first time [2]. A combination of STM and X-ray photodiffraction helps the understanding of chirality transfer from molecules to crystal surfaces [4]. Furthermore, two recent developments of STM theories are presented: (i) an extension of Chen’s derivative rule [5] for STM simulations including tip-orbital interference effects with demonstrated importance of such effects on the STM contrast for two surface structures: N-doped graphene and a magnetic Mn2H complex on the Ag(111) surface [6]; (ii) a combined tunneling electron charge and vector spin transport theory, which provides the first steps toward the theoretical modeling of high-resolution spin transfer torque imaging [3,7].

References:
[1] K. Palotás et al., Front. Phys. 9, 711 (2014)
[2] G. Mándi et al., J. Phys.: Condens. Matter 26, 485007 (2014), Prog. Surf. Sci. 90, 223 (2015)
[3] K. Palotás et al., Phys. Rev. B 96, 024410 (2017), Phys. Rev. B 97, 174402 (2018), Phys. Rev. B 98, 094409 (2018)
[4] W. Xiao et al., Nature Chem. 8, 326 (2016)
[5] C. J. Chen, Phys. Rev. B 42, 8841 (1990)
[6] G. Mándi, K. Palotás, Phys. Rev. B 91, 165406 (2015)
[7] K. Palotás et al., Phys. Rev. B 94, 064434 (2016)

Time

(Friday) 10:00 am - 11:00 am KST

Location

Saturn Seminar Room

3F-367, Research Cooperation Building, 52 Ewhayeodae-gil, Daehyeon-dong

Learn More

Calendar GoogleCal

09dec2:00 pm3:30 pmThomas RisseInstitute of Chemistry and Biochemistry, Freie Universität Berlin2:00 pm - 3:30 pm KST Saturn Seminar Room

Event Details

Thomas Risse

Academic Affiliation: Institute of Chemistry and Biochemistry, Freie Universität Berlin

Talk: December 13, 2019

Charge transfer processes on well-defined heterogeneous model catalysts: an EPR perspective

Surfaces and their interaction with the surrounding environment play a pivotal role in a large variety of technical applications ranging from heterogeneous catalysis, coatings all the way to biological systems. Gaining insight into these systems at the atomic level is one of the key goals of today’s research, however, it is still challenging for most of the complex technological systems. With respect to heterogeneous catalysis oxides play an important role both as support material for metal nano-particles or as catalysts themselves. It is well established that much of the chemical processes at such surfaces do not happen on ideal stoichiometric low index surfaces. Instead higher index surfaces, structural defects like steps, vacancies in the lattice or thin oxide films grown on metal nano-particles -commonly referred to as the strong metal support (SMSI) effect- are important to understand the properties of the surfaces. Even though this is known for quite some time a characterization at the atomic level and an elucidation of the impact on the chemical properties is still challenging. One strategy to gain insight into these properties is using well-defined model systems which grasp essential aspects of the systems of interest but can be studied with the rigor of modern surface science methodology. In this presentation it will be shown how electron paramagnetic resonance (EPR) spectroscopy, a tool rarely used in surface science, can help to gain insight into the properties of defect sites as well as their impact on chemical and physical properties of the surfaces.

The presentation will focus on results obtained on single crystalline, epitaxial MgO oxide films grown on metal single crystal surfaces and discuss charge transfer processes that are unexpected to take place in stochiometric MgO, but become important in case paramagnetic point defects such as color center or transition metal dopants are present in the system. The role of these sites for the activation of small molecules by charge transfer will be elucidated using molecular oxygen a key ingredient for oxidation catalysis. Furthermore, it will be shown that such charge transfer processes, which are considered to be important for catalysis cannot only be induced by defect sites, but may also happen on stoichiometric oxide surfaces in case the oxide is present as an ultrathin film on a metal surface. The evidence based on EPR spectroscopy as well as tunneling microscopy for these processes and the implication of this for catalysis will be discussed.

Time

(Monday) 2:00 pm - 3:30 pm KST

Location

Saturn Seminar Room

3F-367, Research Cooperation Building, 52 Ewhayeodae-gil, Daehyeon-dong

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09decallday20Jacob RepickyThe Ohio State University(All Day) KST Saturn Seminar Room

Event Details

Jacob Repicky

Academic Affiliation: The Ohio State University

Research Area: Low-Temperature Scanning Tunneling Microscopy

Period of Stay: December 9 – 21, 2019

During the stay Mr. Repicky will give a talk in our center:

Date and Location: December 18th, 2019 / Saturn Seminar Room

Magnetic Textures in Chiral Magnet MnGe Observed with SP-STM

Materials with non-centrosymmetric crystal structures can host chiral spin states including magnetic skyrmions. Bulk MnGe hosts a short period magnetic state (3 nm), whose structure depends strongly on atomic lattice strain, and shows a large emergent transport signature associated with the skyrmion phase. Here, we use low-temperature (5 K) spin-polarized scanning tunneling microscopy (SP-STM) to image the magnetic textures in MnGe thin films grown via molecular beam epitaxy and study the influence of the surface on those textures. Most microscopic locations show a spin spiral phase with a 6-8 nm period and a propagation direction that is influenced by step edges, surface termination, and strain. We also report the presence of isolated target skyrmions that likely form due to local modulations in the atomic structure. The skyrmions have a triangular shape which appears to be set by the in-plane lattice vectors, and a core size of approximately 15 nm. We observe the target state is significantly more sensitive to magnetic fields than the spiral phase, and that local voltage and current pulses with the STM tip imply the texture can be ‘switched’ between states with different topological charge. To fully understand the magnetic textures in MnGe we will expand this study by investigating films of different thicknesses to vary the magnetic anisotropy.

Time

december 9 (Monday) - 20 (Friday) KST

Location

Saturn Seminar Room

3F-367, Research Cooperation Building, 52 Ewhayeodae-gil, Daehyeon-dong

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november 2019

21nov2:00 pm3:00 pmQing HuanInstitute of Physics, CAS2:00 pm - 3:00 pm KST Saturn Seminar Room

13nov11:00 am12:00 pmDoohee ChoDepartment of Physics, Yonsei University11:00 am - 12:00 pm KST Saturn Seminar Room

11novallday15Christian AstMax-Planck-Institute for Solid State Research, Germany(All Day) KST Saturn Seminar Room

Event Details

Christian Ast

Affiliation: Max-Planck-Institute for Solid State Research, Germany

Research Field: Quantum Limits in Scanning Tunneling Microscopy, Superconductivity

During his stay Dr. Christian Ast will give 3 seminars in our center:

1. Introduction to Superconductivity and Scanning Tunneling Microscopy

November 11, 14:00 – 15:00

Scanning tunneling microscopy (STM) is the most important experimental tool to explore the world of nanoscience due to its unique capabilities to resolve single atomic structures. STM exploits the tunneling effect to feel the topography of the sample surface at picometer length scales. Beyond the imaging functionality, the tunneling electrons themselves carry a wealth of information about the electronic properties of the substrate. This becomes particularly interesting when superconductivity is involved, because the elementary excitation in a superconductor is a Bogoliubov quasiparticle, a linear superposition of an electron and a hole, but only electrons or holes can tunnel. I will give an introduction to the basics of tunneling in the STM with a particular focus on tunneling between superconductors.

2. Experimental Details of a Dilution Fridge STM

November 12, 14:00 – 15:00

Reaching lowest temperatures in scanning tunneling microscopy (STM) requires combining the microscope with a dilution refrigerator, which triggers interesting technical. Most importantly, a dilution fridge is not a quiet piece of equipment, but STM requires the lowest noise possible. Even measuring temperature becomes a non-trivial problem. Also, the choice of materials that perform well at lowest temperatures, but are at the same time suitable for sample preparation at high temperatures is very limited. Furthermore, modeling the tunnel junction to interpret the experimental data at mK temperatures requires to go beyond the tunnel junction itself to macroscopic scales. The lower the temperature, the more the experiment becomes part of the experiment. I will discuss the challenges of building a mK-STM and interpreting the experimental data, which in the end leads to a much better understanding of the tunneling process as a whole.

3. Sensing the Quantum Limits in Scanning Tunneling Spectroscopy

November 14, 14:00 – 15:00

Sixty years ago in December 1959, when Richard Feynman said that there is “Plenty of Room at the Bottom”, he envisioned the seemingly endless possibilities of the microscopic world, which we now refer to as Nanoscience. However, his statement also implies that there is a bottom meaning that there is a limit to the miniaturization of every process. I will discuss the fundamental limits of transport in scanning tunneling microscopy. This concerns, for example, the changes in the tunneling process imposed by revealing the quantum nature of the electron charge at extremely low temperatures. Further, we exploit magnetic impurities coupled to a superconductor to create single quasiparticle levels inside the superconducting gap (Yu-Shiba-Rusinov states). I will show how we use these states to demonstrate the bare minimum of what is necessary to create a tunneling current.

Time

november 11 (Monday) - 15 (Friday) KST

Location

Saturn Seminar Room

3F-367, Research Cooperation Building, 52 Ewhayeodae-gil, Daehyeon-dong

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october 2019

29oct10:00 am11:30 amYu WangTohoku University, Sendai, Japan10:00 am - 11:30 am KST Saturn Seminar Room

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Yu Wang

Affiliation: Tohoku University, Sendai, Japan

Scanning Tunneling Micrososcopy(STM) Study of Supramolecule Formation and Spin Properties of Radical Molecules of Cobalt Tetrakis(1,2,5-thiadizole) Porphyrazine(CoTTDPz) and 1,3,5-Trithia-2,4,6-Triazapentalenyl(TTTA)

Organic molecule films adsorbed on metal substrates have been widely reported because of the potential application on electronic devices. In this context, metallo-phthalocyanines (MPcs) and their derivatives are intensively studied. However, most of related works above are based on weak molecule-molecule interaction system while a series of Pc derivatives with strong intermolecular force have been synthesized, called metallo-tetrakis(1,2,5-thiadiazole) porphyrazines (MTTDPz). LT-STM study of CoTTDPz on Au(111) from sub-monolayer to multilayer will be introduced in this talk. Image and STS are applied to characterize the bonding configuration and electronic properties of molecules. In addition, the spin properties of CoTTDPz have been studied by detecting Kondo feature on molecules, which show different behaviours form CoPc.

STM observation of TTTA on Au(111) is also described. It belongs to heterocyclic π-radicals family which have been widely studied in recent years, because of the reversible process that the dimers are disposed to thermally driven dimer (S=0) to radical (S=1/2). In my experiment, coverage of TTTA is controlled by adjusting exposing time and annealing. When coverage is near 1 monolayer, two types of TTTA-Au coordination are confirmed and both of them have chirality, electrostatic bonding was also observed in lattice which only appeared between two identical arrays. At low coverage, hierarchical structures made up by threefold units were dominating, the height of Au adatoms are higher than those in arrays. While the mixture of the two structures occurred without initial annealing, this work was probably the first real space observation of TTTA.

Time

(Tuesday) 10:00 am - 11:30 am KST

Location

Saturn Seminar Room

3F-367, Research Cooperation Building, 52 Ewhayeodae-gil, Daehyeon-dong

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04oct11:00 am12:00 pmTyler CockerMichigan State University, USA11:00 am - 12:00 pm KST Saturn Seminar Room

23sepallday11octStefano AgrestiniALBA Synchrotron Light Source(All Day) KST

september 2019

25sep(sep 25)9:00 am27(sep 27)6:00 pmIBS Conference Invited SpeakersCenter for Quantum Nanoscience at Ewha Womans University in Seoul, South Korea9:00 am - 6:00 pm (27) KST Lee SamBong Hall, ECC

01sepallday30Deung-Jang ChoiCentro de Física de Materiales (CSIC-UPV/EHU)(All Day) KST

31augallday02sepWolf-Dieter SchneiderÉcole polytechnique fédérale de Lausanne(All Day)

12augallday19sepKatharina J. FrankeFreie Universität Berlin(All Day) KST

august 2019

12aug2:00 pm3:00 pmHerve AubinCNRS - University Paris-Saclay2:00 pm - 3:00 pm KST

Event Details

Herve Aubin

Affiliation: CNRS – University Paris-Saclay

Talk: August 12th,2019

Research Field: STM – spectroscopy, Quantum effects on superconductivity

Hybrid semiconducting-superconducting systems and superconductivity at the Anderson limit

Hybrid semiconducting-superconducting systems have attracted intense interest because of their potential applications to the fields of superconducting spintronic and topological superconductivity. After a brief overview of hybrid superconducting-semiconducting systems, including some recent works in our group [1,2], I will present a scanning tunneling spectroscopy study of superconducting lead (Pb) nanocrystals grown on the (110) surface of InAs.

The existence of Cooper pairing and the nature of superfluid order in clusters with a small number of Fermions are questions of fundamental interest that have implications for various systems, from atomic nucleus to Helium clusters and superconducting nanocrystals. With its atomic resolution capabilities, STM is an ideal instrument for the study of the electronic spectrum of small size superconducting nanocrystals. Yet, so far, such studies have been hampered by the two antagonistic requirements that the substrate must be conducting and the nanocrystals only weakly coupled to this substrate.Instead of a simple metallic substrate, we found that the 2D electron gas of large Fermi wavelength at the surface of InAs provides an ideal substrate for the growth and study of superconducting lead (Pb) nanocrystals in the regime of quantum confinement.

This discovery allowed to study, for the first time by STM, the superconducting parity effect in nanocrystals as function of their volume and to demonstrate unambiguously the validity of the Anderson criterion, conjectured in 1959, for the existence of superconductivity in nanocrystals submitted to quantum size effects [3].

References:
1. Assouline, A. et al. Spin-Orbit induced phase-shift in Bi2Se3 Josephson junctions.
Nat. Commun. 10, 126 (2019).
2. Assouline, A. et al. Shiba Bound States across the Mobility Edge in Doped InAs Nanowires.
Phys. Rev. Lett. 119, 097701 (2017).
3. Vlaic, S. et al. Superconducting parity effect across the Anderson limit.
Nat. Commun. 8, 14549 (2017).

Time

(Monday) 2:00 pm - 3:00 pm

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09aug11:00 am12:00 pmRomain StompZurich Instruments AG11:00 am - 12:00 pm KST

july 2019

04jul1:00 pm2:00 pmSungmin KimNational Institute of Standards and Technology, MD, United States1:00 pm - 2:00 pm KST

01jul1:00 pm2:00 pmKyung Soo ChoiInstitute for Quantum Computing/University of Waterloo & the Perimeter Institute for Theoretical Physics1:00 pm - 2:00 pm KST

Event Details

Kyung Soo Choi

Affiliation: Institute for Quantum Computing/University of Waterloo & the Perimeter Institute for Theoretical Physics

Talk: July 1, 2019

Many-body quantum electrodynamics (QED) with atoms and photons: A new platform for quantum optics

An exciting frontier in quantum information science is the creation and manipulation of quantum systems that are built and controlled quanta by quanta. In this context, there is an active research worldwide to achieve strong and coherent coupling between light and matter as the building block of complex quantum systems. Despite the range of physical behaviours accessible by these QED systems, the low-energy description is inherently masked by mean fields or renormalization groups

In contrast, I describe our comprehensive theory/experiment program towards synthetic quantum matter, where highly-correlated Rydberg quantum material is strongly coupled to quantized optical cavity fields. We call this new domain of quantum optics, “many-body quantum electrodynamics,” where locally gauged quantum materials are entirely driven by quantum optical fluctuations. I describe our initial laboratory effort towards stabilizing a 2D U(1) quantum spin liquid and the observation of cavity-mediated multiparticle plaquette dynamics, corresponding to an emergent visonic topological defect excitation, for the magnetic flux of the compact dynamical gauge field.

From a broader perspective, our work towards many-body QED will open exhilarating opportunities in atomic and condensed matter physics, and quantum information science to explore the consequential features of macroscopic universes living within strongly-correlated systems, and to help answer some of the most profound questions in physics and computer science — from Baryonic asymmetry, to quantum gravity, and to the quantum Church-Turing thesis. We believe that many-body QED is an essential endeavour for our very instinct to explore genuinely surprising phenomena arising from highly-entangled quantum matter, by light.

Time

(Monday) 1:00 pm - 2:00 pm

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june 2019

14jun1:00 pm2:00 pmQing HuanInstitute of Physics, Chinese Academy of Sciences1:00 pm - 2:00 pm KST

12jun1:00 pm2:00 pmEster NijrolderRadboud University Nijmegen1:00 pm - 2:00 pm KST

05jun11:00 am12:00 pmKarina MorgensternRuhr-Universität Bochum11:00 am - 12:00 pm KST

04jun4:00 pm5:00 pmKarsten ReuterTechnische Universität München4:00 pm - 5:00 pm

Event Details

Karsten Reuter

Academic Affiliation: Technische Universität München

Prof. Reuter’s (b. 1970) research activities are mainly focused on quantitative modeling of material properties and functionalities. Heterogeneous catalysis is a particular area of interest. He makes widespread use of modern multiscale modeling, which unites methods and concepts from the disciplines of physics and chemistry as well as materials science and engineering.

Talk: June 4, 2019

Knowledge-Based Approaches in Catalysis and Energy Modelling

Reflecting the general data revolution, knowledge-based methods are now also entering theoretical catalysis and energy related research with full might. Automatized workflows and the training of machine learning approaches with first-principles data generate predictive-quality insight into elementary processes and process energetics at undreamed-of pace. Computational screening and data mining allows to explore these data bases for promising materials and extract correlations like structure-property relationships. At present, these efforts are still largely based on highly reductionist models that break down the complex interdependencies of working catalyst and energy conversion systems into a tractable number of so-called descriptors, i.e. microscopic parameters that are believed to govern the macroscopic function. For certain classes of materials like transition metal catalysts, corresponding human-designed models have indeed established trend understanding and spurred a targeted materials design. Future efforts will concentrate on using artificial intelligence also in the actual generation and reinforced improvement of the reductionist models. This is expected to better capture complexities like incomplete understanding or operando changes of interfacial morphology, to provide access to structured and compound materials classes, or ultimately to even fulfill the dream of an inverse (de novo) design from function to structure. In this talk, I will briefly survey these developments, providing examples from our own research, in particular on adsorption energetics at bimetallic catalysts and data mining for the design of organic semiconductors.

Time

(Tuesday) 4:00 pm - 5:00 pm

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may 2019

27may(may 27)6:00 am30(may 30)9:00 pmTheory Workshop Invited SpeakersCenter for Quantum Nanoscience at Ewha Womans University in Seoul, South Korea6:00 am - 9:00 pm (30) KST ECC Building, Ewha Womans University

april 2019

15apr1:30 pm2:30 pmSee-Hun YangIBM Research – Almaden1:30 pm - 2:30 pm KST

Event Details

See-Hun Yang

Academic Affiliation: IBM Research – Almaden

Talk: June 4, 2019

Chiral Spintronics

Chirality is one of the fundamental asymmetries in nature. Objects with chirality cannot be superimposed onto each other after mirror reflection operation like right and left hands. Archetypal examples of chiral objects are chiral molecules in stereroisomers and chiral magnetic domain walls whose chiralities are set by e.g. Dzyaloshinskii-Moriya interaction. Most importantly moving spins become chiral such that they can reciprocally interact with chiral objects thus allowing “Chiral Spintronics”. This means that spins traveling in a chiral object can be polarized or reversely spin angular momentum can be transferred to the chiral structure. In this talk I will review this emerging new field, the marriage of spintronics to chirality, by discussing recently discovered various novel torques and phenomena from chiral magnetic nanostructures to chiral molecules: spin-orbit torques from perpendicularly magnetized ultrathin films [1], exchange coupling torque [2] and novel new phase of domain wall dynamic, chiral exchange drag [3] from synthetic antiferromagnets, and efficient separation of chiral molecules, enantiomers, by magnetic structure [4]. In the end I will give an overall outlook on Chiral Spintronics and discuss potential applications from the new findings.

[1] K.-S. Ryu, L. Thomas, S.-H. Yang, and S. S. P. Parkin, “Chiral spin torque at magnetic domain walls”, Nat. Nano. 8, 527 (2013).
[2] S.-H. Yang, K.-S. Ryu, and S. S. P. Parkin, “Domain-wall velocities of up to 750 m s−1 driven by exchange-coupling torque in synthetic antiferromagnets“, Nat. Nano. 10, 221 (2015).
[3] S.-H. Yang, C. Garg, and S. S. P. Parkin, “Chiral Exchange Drag and Chirality Oscillations in Synthetic Antiferromagnets”, Nature Physics 10.1038/s41567-019-04383 (2019).
[4] K. Banerjee-Ghosh, O.B. Dor, F. Tassinari, E. Capua, S. Yochelis, A. Capua, S.-H. Yang, S.S.P. Parkin, S. Sarkar, L. Kronik, L. T. Baczewski, R. Naaman, and Y. Paltiel, “Separation of enantiomers by their enantiospecific interaction with achiral magnetic substrates”, Science 360, 1331 (2018).

Time

(Monday) 1:30 pm - 2:30 pm

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march 2019

13mar11:00 am12:00 amTony LowDepartment of Electrical & Computer Engineering, University of Minnesota, Minneapolis, US11:00 am - 12:00 am KST

february 2019

26feballday27Sebastian LothInstitute for Functional Matter and Quantum Technologies, University of Stuttgart, Germany(All Day) KST

15feb2:00 pm3:00 pmYing JiangInternational Center for Quantum Materials, School of Physics, Peking University2:00 pm - 3:00 pm

11feb11:00 am12:00 amShaoxiang ShengUniversity of Stuttgart, Germany11:00 am - 12:00 am KST

january 2019

09jan2:00 pm3:00 pmSang-Yun LeeCenter for Quantum Information, KIST2:00 pm - 3:00 pm

Event Details

Sang-Yun Lee

Academic Affiliation: Center for Quantum Information, KIST

Talk: January 9, 2019

Color centers in wide bandgap semiconductors for quantum applications

High purity single crystalline solids can be used as a robust platform for quantum information research since isolated point-defects, which resemble isolated single atoms when phonon coupling is efficiently suppressed, can be created in the middle of the almost noise-free environment. Among point-defects which can be created artificially, color center in wide-bandgap semiconductors such as diamond and silicon carbide have been used to demonstrate various proof-of-idea experiments for quantum information and also quantum applications such as quantum metrology. Even though small size integrated qubit devices consisting of a few entangled spin qubits have been demonstrated, there remain open questions about whether this physical system will allow building large quantum devices in which many qubits can interact with each other without losing their coherent properties.
Managing spin-spin interaction among defects spins near each other is a typical method to enable quantum connection among spin qubits. In addition, the optical transitions strongly correlated with spin states of the color centers allow another pathway for integrating individual qubits. One example is the photonic quantum network which can meditate entanglement among distant spin qubits via spin-selective optical transitions. The spin-to-photon interface based on a color center in diamond has shown the entanglement rate exceeding the decoherence rate of two distant spin qubits. In parallel, there have been efforts for finding novel color centers in various large bandgap materials whose ability as a spin-to-photon interface may exceed that of the diamond color centers. The color centers in silicon carbide are candidates since well-developed device fabrication techniques exist and efficient spin-to-photon interfaces have been found recently. In this presentation, a broad review of the quantum technology based on color centers in solids will be provided, and a summary about recent progress will be presented as well.