Team Leader
Spins on Surfaces with Ensemble Techniques
Fabio Donati
Fabio Donati’s research focuses on the magnetism and quantum coherence of surface-supported individual atoms and molecules. His main achievement is the discovery of magnetic stability in single rare earth atoms, a result that proves the possibility of downscaling magnetic memories down to the ultimate limit of an atom. His experimental expertise includes X-ray Magnetic Circular Dichroism (XMCD), Scanning Tunneling Microscopy (STM) and Electron Spin Resonance (ESR).
“There are only two possible conclusions: if the result confirms the hypothesis, then you have just made a measure. If the result is contrary to the hypothesis, then you made a discovery”
Enrico Fermi
- Education
- Work Experience
- Selected Publications
| 2010 | PhD in Radiation Science and Technology, Politecnico di Milano, Italy |
| 2006 | MS in Physics Engineering, Politecnico di Milano, Italy |
| 2004 | BS in Physics Engineering, Politecnico di Milano, Italy |
| 2023- current | Associate Professor at Center for Quantum Nanoscience(QNS), Institute for Basic Science(IBS), Ewha Womans University, Seoul, Korea |
| 2019 – 2023 | Assistant Professor at Center for Quantum Nanoscience(QNS), Institute for Basic Science(IBS), Ewha Womans University, Seoul, Korea |
| 2017 – 2019 | Research Professor at Ewha Womans University, Research Fellow at the IBS center for Quantum Nanoscience |
| 2011 – 2017 | Post-Doc at Ecole Polytechnique Federale de Lausanne, Switzerland |
| 2010 – 2011 | Post-Doc at Politecnico di Milano, Italy” |
2024
Reale S; Hwang J; Oh J; Brune H; Heinrich A J; Donati F; Bae Y
Electrically driven spin resonance of 4f electrons in a single atom on a surface Journal Article
In: Nature Communications, vol. 15, no. 1, pp. 5289, 2024, ISSN: 20411723.
@article{Reale2024,
title = {Electrically driven spin resonance of 4f electrons in a single atom on a surface},
author = {Stefano Reale and Jiyoon Hwang and Jeongmin Oh and Harald Brune and Andreas J Heinrich and Fabio Donati and Yujeong Bae},
url = {https://www.nature.com/articles/s41467-024-49447-y},
doi = {10.1038/s41467-024-49447-y},
issn = {20411723},
year = {2024},
date = {2024-06-01},
urldate = {2024-06-01},
journal = {Nature Communications},
volume = {15},
number = {1},
pages = {5289},
publisher = {Springer Science and Business Media LLC},
abstract = {A pivotal challenge in quantum technologies lies in reconciling long coherence times with efficient manipulation of the quantum states of a system. Lanthanide atoms, with their well-localized 4f electrons, emerge as a promising solution to this dilemma if provided with a rational design for manipulation and detection. Here we construct tailored spin structures to perform electron spin resonance on a single lanthanide atom using a scanning tunneling microscope. A magnetically coupled structure made of an erbium and a titanium atom enables us to both drive the erbium's 4f electron spins and indirectly probe them through the titanium's 3d electrons. The erbium spin states exhibit an extended spin relaxation time and a higher driving efficiency compared to 3d atoms with spin ½ in similarly coupled structures. Our work provides a new approach to accessing highly protected spin states, enabling their coherent control in an all-electric fashion.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A pivotal challenge in quantum technologies lies in reconciling long coherence times with efficient manipulation of the quantum states of a system. Lanthanide atoms, with their well-localized 4f electrons, emerge as a promising solution to this dilemma if provided with a rational design for manipulation and detection. Here we construct tailored spin structures to perform electron spin resonance on a single lanthanide atom using a scanning tunneling microscope. A magnetically coupled structure made of an erbium and a titanium atom enables us to both drive the erbium's 4f electron spins and indirectly probe them through the titanium's 3d electrons. The erbium spin states exhibit an extended spin relaxation time and a higher driving efficiency compared to 3d atoms with spin ½ in similarly coupled structures. Our work provides a new approach to accessing highly protected spin states, enabling their coherent control in an all-electric fashion.
Cho F H; Park J; Oh S; Yu J; Jeong Y; Colazzo L; Spree L; Hommel C; Ardavan A; Boero G; Donati F
In: Review of Scientific Instruments, vol. 95, no. 6, 2024, ISSN: 0034-6748.
@article{Cho2024,
title = {A continuous-wave and pulsed X-band electron spin resonance spectrometer operating in ultra-high vacuum for the study of low dimensional spin ensembles},
author = {Franklin H Cho and Juyoung Park and Soyoung Oh and Jisoo Yu and Yejin Jeong and Luciano Colazzo and Lukas Spree and Caroline Hommel and Arzhang Ardavan and Giovanni Boero and Fabio Donati},
url = {https://pubs.aip.org/rsi/article/95/6/063904/3297917/A-continuous-wave-and-pulsed-X-band-electron-spin},
doi = {10.1063/5.0189974},
issn = {0034-6748},
year = {2024},
date = {2024-06-01},
urldate = {2024-06-01},
journal = {Review of Scientific Instruments},
volume = {95},
number = {6},
publisher = {AIP Publishing},
abstract = {We report the development of a continuous-wave and pulsed X-band electron spin resonance (ESR) spectrometer for the study of spins on ordered surfaces down to cryogenic temperatures. The spectrometer operates in ultra-high vacuum and utilizes a half-wavelength microstrip line resonator realized using epitaxially grown copper films on single crystal Al2O3 substrates. The one-dimensional microstrip line resonator exhibits a quality factor of more than 200 at room temperature, close to the upper limit determined by radiation losses. The surface characterizations of the copper strip of the resonator by atomic force microscopy, low-energy electron diffraction, and scanning tunneling microscopy show that the surface is atomically clean, flat, and single crystalline. Measuring the ESR spectrum at 15 K from a few nm thick molecular film of YPc2, we find a continuous-wave ESR sensitivity of 2.6 × 1011 spins/G · Hz1/2, indicating that a signal-to-noise ratio of 3.9 G · Hz1/2 is expected from a monolayer of YPc2 molecules. Advanced pulsed ESR experimental capabilities, including dynamical decoupling and electron-nuclear double resonance, are demonstrated using free radicals diluted in a glassy matrix.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We report the development of a continuous-wave and pulsed X-band electron spin resonance (ESR) spectrometer for the study of spins on ordered surfaces down to cryogenic temperatures. The spectrometer operates in ultra-high vacuum and utilizes a half-wavelength microstrip line resonator realized using epitaxially grown copper films on single crystal Al2O3 substrates. The one-dimensional microstrip line resonator exhibits a quality factor of more than 200 at room temperature, close to the upper limit determined by radiation losses. The surface characterizations of the copper strip of the resonator by atomic force microscopy, low-energy electron diffraction, and scanning tunneling microscopy show that the surface is atomically clean, flat, and single crystalline. Measuring the ESR spectrum at 15 K from a few nm thick molecular film of YPc2, we find a continuous-wave ESR sensitivity of 2.6 × 1011 spins/G · Hz1/2, indicating that a signal-to-noise ratio of 3.9 G · Hz1/2 is expected from a monolayer of YPc2 molecules. Advanced pulsed ESR experimental capabilities, including dynamical decoupling and electron-nuclear double resonance, are demonstrated using free radicals diluted in a glassy matrix.
2021
Singha A; Sostina D; Wolf C; Ahmed S L; Krylov D; Colazzo L; Gargiani P; Agrestini S; Noh W S; Park J H; Pivetta M; Rusponi S; Brune H; Heinrich A J; Barla A; Donati F
Mapping Orbital-Resolved Magnetism in Single Lanthanide Atoms Journal Article
In: ACS Nano, vol. 15, no. 10, pp. 16162–16171, 2021, ISSN: 1936086X.
@article{Singha2021a,
title = {Mapping Orbital-Resolved Magnetism in Single Lanthanide Atoms},
author = {Aparajita Singha and Daria Sostina and Christoph Wolf and Safa L Ahmed and Denis Krylov and Luciano Colazzo and Pierluigi Gargiani and Stefano Agrestini and Woo Suk Noh and Jae Hoon Park and Marina Pivetta and Stefano Rusponi and Harald Brune and Andreas J Heinrich and Alessandro Barla and Fabio Donati},
url = {https://pubs.acs.org/doi/10.1021/acsnano.1c05026},
doi = {10.1021/acsnano.1c05026},
issn = {1936086X},
year = {2021},
date = {2021-10-01},
urldate = {2021-10-01},
journal = {ACS Nano},
volume = {15},
number = {10},
pages = {16162–16171},
publisher = {American Chemical Society (ACS)},
abstract = {Single lanthanide atoms and molecules are promising candidates for atomic data storage and quantum logic due to the long lifetime of their magnetic quantum states. Accessing and controlling these states through electrical transport requires precise knowledge of their electronic configuration at the level of individual atomic orbitals, especially of the outer shells involved in transport. However, no experimental techniques have so far shown the required sensitivity to probe single atoms with orbital selectivity. Here we resolve the magnetism of individual orbitals in Gd and Ho single atoms on MgO/Ag(100) by combining X-ray magnetic circular dichroism with multiplet calculations and density functional theory. In contrast to the usual assumption of bulk-like occupation of the different electronic shells, we establish a charge transfer mechanism leading to an unconventional singly ionized configuration. Our work identifies the role of the valence electrons in determining the quantum level structure and spin-dependent transport properties of lanthanide-based nanomagnets.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Single lanthanide atoms and molecules are promising candidates for atomic data storage and quantum logic due to the long lifetime of their magnetic quantum states. Accessing and controlling these states through electrical transport requires precise knowledge of their electronic configuration at the level of individual atomic orbitals, especially of the outer shells involved in transport. However, no experimental techniques have so far shown the required sensitivity to probe single atoms with orbital selectivity. Here we resolve the magnetism of individual orbitals in Gd and Ho single atoms on MgO/Ag(100) by combining X-ray magnetic circular dichroism with multiplet calculations and density functional theory. In contrast to the usual assumption of bulk-like occupation of the different electronic shells, we establish a charge transfer mechanism leading to an unconventional singly ionized configuration. Our work identifies the role of the valence electrons in determining the quantum level structure and spin-dependent transport properties of lanthanide-based nanomagnets.
2017
Singha A; Baltic R; Donati F; Wäckerlin C; Dreiser J; Persichetti L; Stepanow S; Gambardella P; Rusponi S; Brune H
4f occupancy and magnetism of rare-earth atoms adsorbed on metal substrates Journal Article
In: Physical Review B, vol. 96, no. 22, pp. 224418, 2017, ISSN: 24699969.
@article{Singha2017,
title = {4f occupancy and magnetism of rare-earth atoms adsorbed on metal substrates},
author = {Aparajita Singha and Romana Baltic and Fabio Donati and Christian Wäckerlin and Jan Dreiser and Luca Persichetti and Sebastian Stepanow and Pietro Gambardella and Stefano Rusponi and Harald Brune},
url = {https://link.aps.org/doi/10.1103/PhysRevB.96.224418},
doi = {10.1103/PhysRevB.96.224418},
issn = {24699969},
year = {2017},
date = {2017-12-01},
urldate = {2017-12-01},
journal = {Physical Review B},
volume = {96},
number = {22},
pages = {224418},
publisher = {IOP Publishing},
abstract = {We report x-ray absorption spectroscopy and x-ray magnetic circular dichroism measurements as well as multiplet calculations for Dy, Ho, Er, and Tm atoms adsorbed on Pt(111), Cu(111), Ag(100), and Ag(111). In the gas phase, all four elements are divalent and we label their 4f occupancy as 4fn. Upon surface adsorption, and depending on the substrate, the atoms either remain in that state or become trivalent with 4fn-1 configuration. The trivalent state is realized when the sum of the atomic correction energies (4f→5d promotion energy Efd+ intershell coupling energy δEc) is low and the surface binding energy is large. The latter correlates with a high substrate density of states at the Fermi level. The magnetocrystalline anisotropy of trivalent RE atoms is larger than the one of divalent RE atoms. We ascribe this to the significantly smaller covalent radius of the trivalent state compared to the divalent one for a given RE element. For a given valency of the RE atom, the anisotropy is determined by the overlap between the spd states of the RE and the d states of the surface. For all investigated systems, the magnetization curves recorded at 2.5 K show absence of hysteresis indicating that magnetic relaxation is faster than about 10 s.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We report x-ray absorption spectroscopy and x-ray magnetic circular dichroism measurements as well as multiplet calculations for Dy, Ho, Er, and Tm atoms adsorbed on Pt(111), Cu(111), Ag(100), and Ag(111). In the gas phase, all four elements are divalent and we label their 4f occupancy as 4fn. Upon surface adsorption, and depending on the substrate, the atoms either remain in that state or become trivalent with 4fn-1 configuration. The trivalent state is realized when the sum of the atomic correction energies (4f→5d promotion energy Efd+ intershell coupling energy δEc) is low and the surface binding energy is large. The latter correlates with a high substrate density of states at the Fermi level. The magnetocrystalline anisotropy of trivalent RE atoms is larger than the one of divalent RE atoms. We ascribe this to the significantly smaller covalent radius of the trivalent state compared to the divalent one for a given RE element. For a given valency of the RE atom, the anisotropy is determined by the overlap between the spd states of the RE and the d states of the surface. For all investigated systems, the magnetization curves recorded at 2.5 K show absence of hysteresis indicating that magnetic relaxation is faster than about 10 s.
2016
Donati F; Rusponi S; Stepanow S; Wäckerlin C; Singha A; Persichetti L; Baltic R; Diller K; Patthey F; Fernandes E; Dreiser J; Šljivančanin Ž; Kummer K; Nistor C; Gambardella P; Brune H
Magnetic remanence in single atoms Journal Article
In: Science, vol. 352, no. 6283, pp. 318–321, 2016, ISSN: 1095-9203.
@article{Donati2016,
title = {Magnetic remanence in single atoms},
author = {F. Donati and S. Rusponi and S. Stepanow and C. Wäckerlin and A. Singha and L. Persichetti and R. Baltic and K. Diller and F. Patthey and E. Fernandes and J. Dreiser and Ž. Šljivančanin and K. Kummer and C. Nistor and P. Gambardella and H. Brune},
doi = {10.1126/science.aad9898},
issn = {1095-9203},
year = {2016},
date = {2016-04-15},
journal = {Science},
volume = {352},
number = {6283},
pages = {318--321},
publisher = {American Association for the Advancement of Science (AAAS)},
abstract = {Stable magnets from single atoms
An important goal in molecular magnetism is to create a permanent magnet from a single atom. Metal atoms adsorbed on surfaces can develop strong magnetization in an applied field (paramagnetism). Donati
et al.
show that single holmium atoms adsorbed on a magnesium oxide film grown on a silver substrate show residual magnetism for temperatures up to 30 K and bistabilty that lasts for 1500 s at 10 K (see the Perspective by Khajetoorians and Heinrich). The atom avoids spin relaxation by a combination of quantum-state symmetry and by the oxide film preventing the spin from interacting with the underlying metal via tunneling.
Science
, this issue p.
318
; see also p.
296
keywords = {},
pubstate = {published},
tppubtype = {article}
}
An important goal in molecular magnetism is to create a permanent magnet from a single atom. Metal atoms adsorbed on surfaces can develop strong magnetization in an applied field (paramagnetism). Donati
show that single holmium atoms adsorbed on a magnesium oxide film grown on a silver substrate show residual magnetism for temperatures up to 30 K and bistabilty that lasts for 1500 s at 10 K (see the Perspective by Khajetoorians and Heinrich). The atom avoids spin relaxation by a combination of quantum-state symmetry and by the oxide film preventing the spin from interacting with the underlying metal via tunneling.
, this issue p.
; see also p.
2014
Rau I G; Baumann S; Rusponi S; Donati F; Stepanow S; Gragnaniello L; Dreiser J; Piamonteze C; Nolting F; Gangopadhyay S; Albertini O R; Macfarlane R M; Lutz C P; Jones B A; Gambardella P; Heinrich A J; Brune H
Reaching the magnetic anisotropy limit of a 3d metal atom Journal Article
In: Science, vol. 344, no. 6187, pp. 988–992, 2014, ISSN: 1095-9203.
@article{Rau2014,
title = {Reaching the magnetic anisotropy limit of a 3d metal atom},
author = {Ileana G. Rau and Susanne Baumann and Stefano Rusponi and Fabio Donati and Sebastian Stepanow and Luca Gragnaniello and Jan Dreiser and Cinthia Piamonteze and Frithjof Nolting and Shruba Gangopadhyay and Oliver R. Albertini and Roger M. Macfarlane and Christopher P. Lutz and Barbara A. Jones and Pietro Gambardella and Andreas J. Heinrich and Harald Brune},
doi = {10.1126/science.1252841},
issn = {1095-9203},
year = {2014},
date = {2014-05-30},
urldate = {2014-05-30},
journal = {Science},
volume = {344},
number = {6187},
pages = {988--992},
publisher = {American Association for the Advancement of Science (AAAS)},
abstract = {<jats:title>Maximizing atomic magnetic memory</jats:title>
<jats:p>
A study of the magnetic response of cobalt atoms adsorbed on oxide surfaces may lead to much denser storage of data. In hard drives, data are stored as magnetic bits; the magnetic field pointing up or down corresponds to storing a zero or a one. The smallest bit possible would be a single atom, but the magnetism of a single atom —its spin—has to be stabilized by interactions with heavy elements or surfaces through an effect called spin-orbit coupling. Rau
<jats:italic>et al.</jats:italic>
(see the Perspective by Khajetoorians and Wiebe) built a model system in pursuit of single-atom bits—cobalt atoms adsorbed on magnesium oxide. At temperatures approaching absolute zero, the stabilization of the spin's magnetic direction reached the maximum that is theoretically possible.
</jats:p>
<jats:p>
<jats:italic>Science</jats:italic>
, this issue p.
<jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6187" page="988" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1252841">988</jats:related-article>
; see also p.
<jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6187" page="976" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1254402">976</jats:related-article>
</jats:p>},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
<jats:title>Maximizing atomic magnetic memory</jats:title>
<jats:p>
A study of the magnetic response of cobalt atoms adsorbed on oxide surfaces may lead to much denser storage of data. In hard drives, data are stored as magnetic bits; the magnetic field pointing up or down corresponds to storing a zero or a one. The smallest bit possible would be a single atom, but the magnetism of a single atom —its spin—has to be stabilized by interactions with heavy elements or surfaces through an effect called spin-orbit coupling. Rau
<jats:italic>et al.</jats:italic>
(see the Perspective by Khajetoorians and Wiebe) built a model system in pursuit of single-atom bits—cobalt atoms adsorbed on magnesium oxide. At temperatures approaching absolute zero, the stabilization of the spin's magnetic direction reached the maximum that is theoretically possible.
</jats:p>
<jats:p>
<jats:italic>Science</jats:italic>
, this issue p.
<jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6187" page="988" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1252841">988</jats:related-article>
; see also p.
<jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6187" page="976" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1254402">976</jats:related-article>
</jats:p>
<jats:p>
A study of the magnetic response of cobalt atoms adsorbed on oxide surfaces may lead to much denser storage of data. In hard drives, data are stored as magnetic bits; the magnetic field pointing up or down corresponds to storing a zero or a one. The smallest bit possible would be a single atom, but the magnetism of a single atom —its spin—has to be stabilized by interactions with heavy elements or surfaces through an effect called spin-orbit coupling. Rau
<jats:italic>et al.</jats:italic>
(see the Perspective by Khajetoorians and Wiebe) built a model system in pursuit of single-atom bits—cobalt atoms adsorbed on magnesium oxide. At temperatures approaching absolute zero, the stabilization of the spin's magnetic direction reached the maximum that is theoretically possible.
</jats:p>
<jats:p>
<jats:italic>Science</jats:italic>
, this issue p.
<jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6187" page="988" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1252841">988</jats:related-article>
; see also p.
<jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6187" page="976" related-article-type="in-this-issue" vol="344" xlink:href="10.1126/science.1254402">976</jats:related-article>
</jats:p>