Katharina J. Franke Affiliation: Freie Universität Berlin Research Field: Scanning Tunneling Microscopy of magnetic adatoms on superconductors, Molecules on surfaces Talk: August 21, 11:00
Katharina J. Franke
Affiliation: Freie Universität Berlin
Research Field: Scanning Tunneling Microscopy of magnetic adatoms on superconductors, Molecules on surfaces
Talk: August 21, 11:00 -12:00
Transport properties through Shiba states
Magnetic adsorbates on conventional s-wave superconductors lead to exchange interactions that can induce bound states inside the superconducting energy gap. These states are known as YuShiba-Rusinov states (or Shiba states) and can be resolved by scanning tunneling spectroscopy as a pair of resonances at positive and negative bias voltages in the superconducting gap. Here, we employ tunneling spectroscopy at 1.1 K to investigate magnetic atoms on a superconducting Pb surface. The single-atom junctions are stable over several orders of magnitude in conductance. We observe two different transport regimes: at large tip-sample distance, the tunneling current is dominated by single-electron processes. However, these require the relaxation of electrons/holes from the Shiba states into the superconductor. At small tip-sample distance, the relaxation processes are not sufficiently fast for an efficient depopulation of the states, and thus Andreev processes become important, which resonantly transfer a Cooper pair into the superconductor. We probe the nature of the two-electron transport processes by irradiating the junction with microwaves from an antenna placed close to the junction. The tunneling electrons absorb or emit photons from the microwave field resulting in a distinct pattern of split Shiba states as a function of irradiation power.
Deung-Jang Choi Affiliation: Centro de Física de Materiales (CSIC-UPV/EHU) Period of Stay: September 1 ~ September 30 Research Field: Nanomagnetism combined with superconductivity The information
september 1 (Sunday) - 30 (Monday)
International IBS Conference on Quantum Nanoscience Date: September 25 - 27, 2019 Location: Lee SamBong Hall, ECC Building, Center for Quantum
International IBS Conference on Quantum Nanoscience
Date: September 25 – 27, 2019
Location: Lee SamBong Hall, ECC Building, Center for Quantum Nanoscience at Ewha Womans University in Seoul, South Korea
There are many conferences that cover subfields of Quantum Nanoscience area but as far as the organizers know, there is currently no conference that attempts to bring this broader community under one roof. We will bring together experts and young scientists from all around the globe in this exciting research topic.
Visit https://icqns.org/ to learn more about our conference.
25 (Wednesday) 9:00 am - 27 (Friday) 6:00 pm
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 Ewha Womans University Science Building DB106
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
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.
(Monday) 1:00 pm - 2:00 pm KST
Sungmin Kim Affiliation: National Institute of Standards and Technology, MD, United States Talk: July 4, 2019 Improvement of milli-Kelvin Scanning Probe Microscope System and
Affiliation: National Institute of Standards and Technology, MD, United States
Talk: July 4, 2019
Improvement of milli-Kelvin Scanning Probe Microscope System and Edge State Studyof Graphene Quantum Hall Device
In this talk, I present the improvement of functionality and energy resolution of tunneling spectroscopy of the NIST milliKelvin SPM system, and recent studies performed by this system on graphene quantum Hall device. The NIST millikelvin SPM system was constructed in 2010 as the first generation of millikelvin STM by using dilution refrigerator, and it has been operated to conduct the number of researches on 2D materials such as graphene, topological insulators. Recently, implementation of qPlus sensor AFM on the SPM module made it overcome the limitation of tunneling current measurement. By applying multi-contact sample holder and auto navigating algorithm we accomplished the in-situ transport measurement. In addition, by combining RF filters and proper electrical grounds, we achieved an ultra-high energy resolution tunneling spectroscopy – better than 10ueV energy resolution – for measuring Josephson peak spectrum on superconductor-superconductor junction, which is the best level of energy resolution in tunneling spectroscopy measurement by using SPM so far. For the analysis of high energy resolution spectroscopy, P(E) model and Maki’s theory are applied. In addition, recent studies of graphene quantum Hall edge state by AFM and KPFM measurements will be introduced.
The information about time and location of the talk will be updated soon.
(Thursday) 1:00 pm - 2:00 pm KST
Karsten Reuter Academic Affiliation: Technische Universität München Prof. Reuter’s (b. 1970) research activities are mainly focused on quantitative modeling of material
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.
(Tuesday) 4:00 pm - 5:00 pm
Karina Morgenstern Academic Affiliation: Ruhr-Universität Bochum Research area: Surface Science Visit Dates: June 5, 2019 STM investigation of laser driven processes at surfaces While
Academic Affiliation: Ruhr-Universität Bochum
Research area: Surface Science
Visit Dates: June 5, 2019
STM investigation of laser driven processes at surfaces
While photochemistry in the gas phase demands a resonant excitation of the molecules, the presence of a metal surface in surface chemistry opens a different pathway via the creation of hot electrons in the metal and subsequent attachment of these energetic electrons to adsorbed molecules. We use two set-ups that combine a low-temperature scanning tunneling microscope operating below 10 K with a frequency doubled femto-second laser and a tunable pico-second laser, respectively, to investigate processes induced by these electrons on a single molecule basis.
In this talk, I will first present recent results on the effect of intense fs-laser illumination on the structure of metal surfaces, in particular Ag(100) and Cu(111). Then I will compare laser-induced diffusion to thermal diffusion of CO molecules on Cu(111). In particular the long-range interaction between diffusing molecules differs in the two cases. Finally, I will present results obtained by electrons attaching to and solvating in different ice structures adsorbed on Cu(111) without and with halogenated (chlorine or bromine) benzene molecules adsorbed on them. These model systems enhance our understanding of the impact of ionizing radiation on the chemical composition of Earth’s upper atmosphere (e.g. its ozone density), which is known to trigger chemical processes at the surfaces of cold ice covered grain particles.
Franklin Cho Talk: June 7, 2019 High-frequency (HF) electron spin resonance (ESR) spectroscopy and ESR based quantum computing Electron spin resonance (ESR)
Talk: June 7, 2019
High-frequency (HF) electron spin resonance (ESR) spectroscopy and ESR based quantum computing
Electron spin resonance (ESR) spectroscopy is a powerful and versatile tool for probing and studying local structures and dynamic properties of various compounds in liquids and solids; for example, structures and dynamics in biological molecules, magnetic structures and relaxations in magnetic molecules and quantum coherence in solid-state spin systems.
High-frequency (HF) ESR spectroscopy is an emerging technique enabling finer spectral resolution, better absolute sensitivity, and improved time resolution. I will first talk about the development of a HF ESR spectrometer at the University of Sothern California [1,2]. The spectrometer consisting of a high-power HF solid-state source, a quasioptical system, a phase-sensitive superheterodyne detection system, a 12.1 Tesla cryogenic-free superconducting magnet, and a 4He cryostat enables pulsed ESR measurements with a few hundred nanosecond pulses. I will also discuss some of its unique experimental capabilities such as double electron-electron resonance and dynamical decoupling to study paramagnetic impurities existing in synthetic diamond crystals.
If time permits, I will then talk about our efforts on ESR based quantum computing at the University of Waterloo, particularly experimental realization of a quantum algorithm known as heat-bath algorithmic cooling using a solid-state electron-nuclear coupled system . A home-built pulsed X-band ESR spectrometer with arbitrary waveform generator is employed (electron-nuclear double resonance capability was added later) . Major focus has been understanding noises and improving quantum control which is critical in the field of quantum computing and quantum information processing [5,6].
 F. H. Cho, V. Stepanov, and S. Takahashi, Review of Scientific Instruments 85, 075110 (2014).
 F. H. Cho, V. Stepanov,C. Abeywardana, and S. Takahashi, Methods in Enzymology 563, 95 (2015)
 D. K. Park, G. Feng, R. Rahimi, S. Labruyère, T. Shibata, S. Nakazawa, K. Sato, T. Takui, R. Laflamme, and J. Baugh, Quantum Information Processing 14, 2435 (2015)
 D. K. Park, G. Feng, R. Rahimi, J. Baugh, and R. Laflamme, Journal of Magnetic Resonance 267, 68 (2016)
 G. Feng, J. J. Wallman, B. Buonacorsi, F. H. Cho, D. K. Park, T. Xin, D. Lu, J. Baugh, and R. Laflamme, Physical Review Letters 117, 260501 (2016)
 G. Feng, F. H. Cho, H. Katiyar, J. Li, D. Lu, J. Baugh, and R. Laflamme, Physical Review A 98, 052341 (2018)
(Friday) 1:30 pm - 2:30 pm KST
Joint Workshop IBS CNM-QNS Talks: June 7, 2019 16:00 - 16:20 - Taeyoung Choi "Single atom electron spin resonance toward atomic
Joint Workshop IBS CNM-QNS
Talks: June 7, 2019
16:00 – 16:20 – Taeyoung Choi “Single atom electron spin resonance toward atomic scale quantum sensor”
16:25 – 16:45 – Kwanpyo Kim “Atomic Structures and E-Beam-Induced Dynamics of 2D van der Waals Heterostructures”
16:55 – 17:10 – IBS CNM – QNS Casual Meeting
(Friday) 4:00 pm - 5:30 pm KST
Ester Nijrolder Academic Affiliation: Radboud University Nijmegen Research area: STM - spectroscopy, quantum effects on superconductivity Visit Dates: June 9 - 15, 2019 Coupled atom
Academic Affiliation: Radboud University Nijmegen
Research area: STM – spectroscopy, quantum effects on superconductivity
Visit Dates: June 9 – 15, 2019
Coupled atom magnetism
In modern times more and more technology is used during the day. All this technology is based on logic operators that work with electric currents. One of the ways to make these logic operators more energy efficient is to make magnetic logic operators. But, to make magnetic logic operators applicable in everyday life, we still need to learn a lot about them. Therefore I’m giving a summary of different types of coupled atom magnetism on surfaces, which eventually could be used to make logic operators consisting of only a few atoms. This is an improvement in both size and energy efficiency, but there is still a long way to go.
(Wednesday) 1:00 pm - 2:00 pm KST
Qing Huan Academic Affiliation: Institute of Physics, Chinese Academy of Sciences Research area: Scan tunneling/probe microscopy, specially instrumentation Visit Dates: June 13, 2019 Recent R&D
Academic Affiliation: Institute of Physics, Chinese Academy of Sciences
Research area: Scan tunneling/probe microscopy, specially instrumentation
Visit Dates: June 13, 2019
Recent R&D progresses on UHV SPM in IOP, CAS – Components and systems
This talk will mainly focus on instrumentation. I will introduce our R&D progresses on UHV-SPM systems and related components, which includes evaporators, electronics, cryostat, scanner heads, the update of a 4-probe STM, Variable-temperature STM, Low-temperature SPM combined with MBE and optical accesses, and Low-temperature STM combined with Combi-LMBE et. al. Some of the test results and research results from these systems will also be shown.
(Friday) 1:00 pm - 2:00 pm KST