Theory of Quantum Systems at Surfaces

Description

The theory team at QNS has two goals:

  1. to be just one door away for every experimentalist and aid in the explanation of new discoveries and
  2. to, in turn, guide experimentalists in our search for novel quantum spin systems on surfaces and interfaces with the goal of achieving full quantum control.


Most of our work to date is based on ab initio modelling within the framework of density functional theory (DFT). This method is suitable for treating large surface systems and small molecules at equal footing, but has some drawbacks when describing magnetic phenomena at the nanoscale due to approximations made in the implementation of DFT.

Spin-polarization isosurfaces of antiferromagnetically coupled nickelocene molecules, a promising candidate as "spin-filter" in STM measurements.

To overcome these limitations, QNS and collaborators have developed tools that go beyond the DFT mean field description and recover the true many-body character of the wavefunction. This allows us to accurately explore the landscape of magnetic energies and, in the near future, also the coherence times of such systems.
1) Wolf, C., Delgado, F., Reina, J. & Lorente, N., Efficient Ab Initio Multiplet Calculations for Magnetic Adatoms on MgO, The Journal of Physical Chemistry A 124, 2318–2327 (2020)
2) Reina Gálvez, J., Wolf, C., Delgado, F. & Lorente, N., Cotunneling mechanism for all-electrical electron spin resonance of single adsorbed atoms, Physical Review B 100, 7–12 (2019)

Low-energy spectrum of the multiplet solution of Fe on MgO under the influence of crystal field, spin-orbit coupling (SO) and magnetic field perpendicular to the sample (Bz)

Most of our work can be performed in-house on our mid-size high-performance computer cluster.

To expand our network, we have recently (May 2019) hosted a workshop that brought together more than 20 experts in the field of theoretical advances of spins at the nanoscale and through our visitor program we have hosted experts from all over the world, making QNS a global hub for theoretical studies of quantum phenomena on surfaces.
 

Long-Term Goals

  • Find surface quantum systems that are promising for the realization of full quantum control using only ab initio-based methods
  • Develop theoretical understanding of quantum coherence, with emphasis on mitigating decoherence
  • Investigate the transition from quantum to classical behavior, including the quantum measurement problem

Near-Term Goals

  • Expanding our studies from d-electron system to the more complex f-electron systems of the lanthanide series
  • Explore more systems for long magnetic lifetime and coherence times
  • Thereby guiding experimentalists in their search for such systems
  • Expand the QNS global hub with long-term and short-term visitors
 

Key Publications

On the magnetic bistability of small iron clusters used in scanning tunneling microscopy tip preparation
Jisoo Yu, Corina Urdaniz, Young Namgoong and Christoph Wolf (2023) ...
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An atomic-scale multi-qubit platform
Yu Wang, Yi Chen, Hong T. Bui, Yujeong Bae, Soo-Hyon Phark, and Andreas J. Heinrich, Christoph Wolf, Masahiro Haze, Cristina ...
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Electric-Field-Driven Spin Resonance by On-Surface Exchange Coupling to a Single-Atom Magnet
Soo-hyon Phark, Hong Thi Bui, Alejandro Ferrón, Joaquin Fernández-Rossier, Jose Reina-Gálvez, Christoph Wolf, Yu Wang, Kai Yang, Andreas J. Heinrich, ...
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Double-Resonance Spectroscopy of Coupled Electron Spins on a Surface
Soo-hyon Phark, Yi Chen, Hong T. Bui, Yu Wang, Masahiro Haze, Jinkyung Kim, Yujeong Bae*, Andreas J. Heinrich*, and Christoph ...
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Many-body nonequilibrium effects in all-electric electron spin resonance
Jose Reina-Gálvez, Christoph Wolf, and Nicolás Lorente (2023) ...
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Template-directed 2D nanopatterning of S = 1/2 molecular spins
Kyungju Noh, Luciano Colazzo, Corina Urdaniz, Jaehyun Lee, Denis Krylov, Parul Devi, Andrin Doll, Andreas J. Heinrich, Christoph Wolf, Fabio ...
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Erbium and thulium on MgO(100)/Ag(100) as candidates for single atom qubits
S. Reale, A. Singha, S. L. Ahmed, D. Krylov, L. Colazzo, C. Wolf, C. S. Casari, A. Barla, E. Fernandes, ...
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Anisotropic Hyperfine Interaction of Surface-Adsorbed Single Atoms
Jinkyung Kim, Kyungju Noh, Yi Chen, Fabio Donati, Andreas J. Heinrich, Christoph Wolf, and Yujeong Bae (2022) ...
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Coherent Spin Control of Single Molecules on a Surface
Philip Willke, Tobias Bilgeri, Xue Zhang, Yu Wang, Christoph Wolf, Herve Aubin, Andreas Heinrich, and Taeyoung Choi(2021) ...
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Electron spin resonance of single iron phthalocyanine molecules and role of their non-localized spins in magnetic interactions
Xue Zhang, Christoph Wolf, Yu Wang, Hervé Aubin, Tobias Bilgeri, Philip Willke, Andreas J. Heinrich & Taeyoung Choi(2021) ...
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Spin resonance amplitude and frequency of a single atom on a surface in a vector magnetic field
Jinkyung Kim, Won-jun Jang, Thi Hong Bui, Deung-Jang Choi, Christoph Wolf, Fernando Delgado, Yi Chen, Denis Krylov, Soonhyeong Lee, Sangwon ...
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Correlation between Electronic Configuration and Magnetic Stability in Dysprosium Single Atom Magnets
Fabio Donati, Marina Pivetta, Christoph Wolf, Aparajita Singha, Christian Wäckerlin, Romana Baltic, Edgar Fernandes, Jean-Guillaume de Groot, Safa Lamia Ahmed, ...
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Mapping Orbital-Resolved Magnetism in Single Lanthanide Atoms
Aparajita Singha, Daria Sostina, Christoph Wolf, Safa L. Ahmed, Denis Krylov, Luciano Colazzo, Pierluigi Gargiani, Stefano Agrestini, Woo-Suk Noh, Jae-Hoon ...
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Atomic-scale intermolecular interaction of hydrogen with a single VOPc molecule on the Au(111) surface
Jinoh Jung, Shinjae Nam, Christoph Wolf, Andreas J. Heinrich and Jungseok Chae, RSC Advances (2021) ...
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Probing Magnetism in Artificial Metal–Organic Complexes Using Electronic Spin Relaxometry
Xue Zhang, Philip Willke, Aparajita Singha, Christoph Wolf, Taner Esat, Minhee Choi, Andreas J. Heinrich, and Taeyoung Choi, Journal of ...
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Growth of Multilayer Graphene with a Built-in Vertical Electric Field
Min Seok Yoo, Hyo Chan Lee, Christoph Wolf, Nguyen Ngan Nguyen, Do-Hyun Park, Jinsung Kim, Eunho Lee, Hyun-Jong Chung, and ...
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Efficient Ab Initio Multiplet Calculations for Magnetic Adatoms on MgO
Christoph Wolf, Fernando Delgado, José Reina, Nicolás Lorente, J. Phys. Chem. A (2020) ...
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Cotunneling mechanism for all-electrical electron spin resonance of single adsorbed atoms
J. Reina Gálvez, C. Wolf, F. Delgado, and N. Lorente, Phys. Rev. B, 2019 ...
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High-Efficiency Polycrystalline Perovskite Light-Emitting Diodes Based on Mixed Cations
Himchan Cho, Joo Sung Kim, Christoph Wolf, Young-Hoon Kim, Hyung Joong Yun, Su-Hun Jeong, Aditya Sadhanala , Vijay Venugopalan , ...
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Members:

  • Christoph Wolf
  • Corina Urdaniz
  • Jose Galvez