1
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Sorrentino AL, Poggini L, Serrano G, Cucinotta G, Cortigiani B, Malavolti L, Parenti F, Otero E, Arrio MA, Sainctavit P, Caneschi A, Cornia A, Sessoli R, Mannini M. Assembling Fe 4 single-molecule magnets on a TiO 2 monolayer. NANOSCALE 2024; 16:14378-14386. [PMID: 38993100 DOI: 10.1039/d4nr02234c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/13/2024]
Abstract
The decoration of technologically relevant surfaces, such as metal oxides, with Single-Molecule Magnets (SMMs) constitutes a persistent challenge for the integration of these molecular systems into novel technologies and, in particular, for the development of spintronic and quantum devices. We used UHV thermal sublimation to deposit tetrairon(III) propeller-shaped SMMs (Fe4) as a single layer on a TiO2 ultrathin film grown on Cu(001). The properties of the molecular deposit were studied using a multi-technique approach based on standard topographic and spectroscopic measurements, which demonstrated that molecules remain largely intact upon deposition. Ultralow temperature X-ray Absorption Spectroscopy (XAS) with linearly and circularly polarized light was further employed to evaluate both the molecular organization and the magnetic properties of the Fe4 monolayer. X-ray Natural Linear Dichroism (XNLD) and X-ray Magnetic Circular Dichroism (XMCD) showed that molecules in a monolayer display a preferential orientation and an open magnetic hysteresis with pronounced quantum tunnelling steps up to 900 mK. However, unexpected extra features in the XAS and XMCD spectra disclosed a minority fraction of altered molecules, suggesting that the TiO2 film may be chemically non-innocent. The observed persistence of SMM behaviour on a metal oxide thin film opens new possibilities for the development of SMM-based hybrid systems.
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Affiliation(s)
- Andrea Luigi Sorrentino
- Department of Industrial Engineering - DIEF - and INSTM Research Unit, University of Florence, Via Santa Marta 3, 50139 Florence, Italy
- Department of Chemistry "U. Schiff" - DICUS - and INSTM Research Unit, University of Florence, Via della Lastruccia 3-13, 50019 Sesto Fiorentino, FI, Italy.
| | - Lorenzo Poggini
- Department of Chemistry "U. Schiff" - DICUS - and INSTM Research Unit, University of Florence, Via della Lastruccia 3-13, 50019 Sesto Fiorentino, FI, Italy.
- Institute for Chemistry of Organo-Metallic Compounds (ICCOM-CNR), Via Madonna del Piano, 50019 Sesto Fiorentino, FI, Italy
| | - Giulia Serrano
- Department of Industrial Engineering - DIEF - and INSTM Research Unit, University of Florence, Via Santa Marta 3, 50139 Florence, Italy
- Department of Chemistry "U. Schiff" - DICUS - and INSTM Research Unit, University of Florence, Via della Lastruccia 3-13, 50019 Sesto Fiorentino, FI, Italy.
| | - Giuseppe Cucinotta
- Department of Chemistry "U. Schiff" - DICUS - and INSTM Research Unit, University of Florence, Via della Lastruccia 3-13, 50019 Sesto Fiorentino, FI, Italy.
| | - Brunetto Cortigiani
- Department of Chemistry "U. Schiff" - DICUS - and INSTM Research Unit, University of Florence, Via della Lastruccia 3-13, 50019 Sesto Fiorentino, FI, Italy.
| | - Luigi Malavolti
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart, Germany
| | - Francesca Parenti
- Department of Chemical and Geological Sciences and INSTM Research Unit, University of Modena and Reggio Emilia, Via G. Campi 103, 41125 Modena, Italy
| | - Edwige Otero
- Synchrotron-SOLEIL, L'Orme des Merisiers, 91192 Saint-Aubin, France
| | - Marie-Anne Arrio
- CNRS UMR7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Sorbonne Université/MNHN, 4 place Jussieu, 75252 Paris Cedex 5, France
| | - Philippe Sainctavit
- Synchrotron-SOLEIL, L'Orme des Merisiers, 91192 Saint-Aubin, France
- CNRS UMR7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Sorbonne Université/MNHN, 4 place Jussieu, 75252 Paris Cedex 5, France
| | - Andrea Caneschi
- Department of Industrial Engineering - DIEF - and INSTM Research Unit, University of Florence, Via Santa Marta 3, 50139 Florence, Italy
| | - Andrea Cornia
- Department of Chemical and Geological Sciences and INSTM Research Unit, University of Modena and Reggio Emilia, Via G. Campi 103, 41125 Modena, Italy
| | - Roberta Sessoli
- Department of Chemistry "U. Schiff" - DICUS - and INSTM Research Unit, University of Florence, Via della Lastruccia 3-13, 50019 Sesto Fiorentino, FI, Italy.
- Institute for Chemistry of Organo-Metallic Compounds (ICCOM-CNR), Via Madonna del Piano, 50019 Sesto Fiorentino, FI, Italy
| | - Matteo Mannini
- Department of Chemistry "U. Schiff" - DICUS - and INSTM Research Unit, University of Florence, Via della Lastruccia 3-13, 50019 Sesto Fiorentino, FI, Italy.
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2
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Budakian R, Finkler A, Eichler A, Poggio M, Degen CL, Tabatabaei S, Lee I, Hammel PC, Eugene SP, Taminiau TH, Walsworth RL, London P, Bleszynski Jayich A, Ajoy A, Pillai A, Wrachtrup J, Jelezko F, Bae Y, Heinrich AJ, Ast CR, Bertet P, Cappellaro P, Bonato C, Altmann Y, Gauger E. Roadmap on nanoscale magnetic resonance imaging. NANOTECHNOLOGY 2024; 35:412001. [PMID: 38744268 DOI: 10.1088/1361-6528/ad4b23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 05/14/2024] [Indexed: 05/16/2024]
Abstract
The field of nanoscale magnetic resonance imaging (NanoMRI) was started 30 years ago. It was motivated by the desire to image single molecules and molecular assemblies, such as proteins and virus particles, with near-atomic spatial resolution and on a length scale of 100 nm. Over the years, the NanoMRI field has also expanded to include the goal of useful high-resolution nuclear magnetic resonance (NMR) spectroscopy of molecules under ambient conditions, including samples up to the micron-scale. The realization of these goals requires the development of spin detection techniques that are many orders of magnitude more sensitive than conventional NMR and MRI, capable of detecting and controlling nanoscale ensembles of spins. Over the years, a number of different technical approaches to NanoMRI have emerged, each possessing a distinct set of capabilities for basic and applied areas of science. The goal of this roadmap article is to report the current state of the art in NanoMRI technologies, outline the areas where they are poised to have impact, identify the challenges that lie ahead, and propose methods to meet these challenges. This roadmap also shows how developments in NanoMRI techniques can lead to breakthroughs in emerging quantum science and technology applications.
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Affiliation(s)
- Raffi Budakian
- Department of Physics and Astronomy, University of Waterloo, Waterloo, Canada
- Institute for Quantum Computing, University of Waterloo, Waterloo, Canada
| | - Amit Finkler
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Alexander Eichler
- Institute for Solid State Physics, ETH Zurich, Otto-Stern-Weg 1, 8093 Zurich, Switzerland
| | - Martino Poggio
- Department of Physics and Swiss Nanoscience Institute, University of Basel, 4056 Basel, Switzerland
| | - Christian L Degen
- Institute for Solid State Physics, ETH Zurich, Otto-Stern-Weg 1, 8093 Zurich, Switzerland
| | - Sahand Tabatabaei
- Department of Physics and Astronomy, University of Waterloo, Waterloo, Canada
- Institute for Quantum Computing, University of Waterloo, Waterloo, Canada
| | - Inhee Lee
- Department of Physics, The Ohio State University, Columbus, OH 43210, United States of America
| | - P Chris Hammel
- Department of Physics, The Ohio State University, Columbus, OH 43210, United States of America
| | - S Polzik Eugene
- Niels Bohr Institute, University of Copenhagen, 17, Copenhagen, 2100, Denmark
| | - Tim H Taminiau
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, Netherlands
| | - Ronald L Walsworth
- University of Maryland 2218 Kim Engineering Building, College Park, MD 20742, United States of America
| | - Paz London
- Department of Physics, University of California, Santa Barbara, CA 93106, United States of America
| | - Ania Bleszynski Jayich
- Department of Physics, University of California, Santa Barbara, CA 93106, United States of America
| | - Ashok Ajoy
- Department of Chemistry, University of California, Berkeley, CA 97420, United States of America
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, CA 94720, United States of America
- Quantum Information Science Program, CIFAR, 661 University Ave., Toronto, ON M5G 1M1, Canada
| | - Arjun Pillai
- Department of Chemistry, University of California, Berkeley, CA 97420, United States of America
| | - Jörg Wrachtrup
- 3. Physikalisches Institut, University of Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Fedor Jelezko
- Institute of Quantum Optics, Ulm University, Ulm, 89081, Germany
| | - Yujeong Bae
- Center for Quantum Nanoscience, Institute for Basic Science, Seoul 03760, Republic of Korea
- Department of Physics, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Andreas J Heinrich
- Center for Quantum Nanoscience, Institute for Basic Science, Seoul 03760, Republic of Korea
- Department of Physics, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Christian R Ast
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Patrice Bertet
- Université Paris-Saclay, CEA, CNRS, SPEC, 91191 Gif-sur-Yvette, France
| | - Paola Cappellaro
- Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, United States of America
| | - Cristian Bonato
- SUPA, Institute of Photonics and Quantum Sciences, School of Engineering and Physical Sciences, HeriotWatt University, Edinburgh EH14 4AS, United Kingdom
| | - Yoann Altmann
- Institute of Signals, Sensors and Systems, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Erik Gauger
- SUPA, Institute of Photonics and Quantum Sciences, School of Engineering and Physical Sciences, HeriotWatt University, Edinburgh EH14 4AS, United Kingdom
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3
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Kovarik S, Schlitz R, Vishwakarma A, Ruckert D, Gambardella P, Stepanow S. Spin torque-driven electron paramagnetic resonance of a single spin in a pentacene molecule. Science 2024; 384:1368-1373. [PMID: 38900895 DOI: 10.1126/science.adh4753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 05/10/2024] [Indexed: 06/22/2024]
Abstract
Control over quantum systems is typically achieved by time-dependent electric or magnetic fields. Alternatively, electronic spins can be controlled by spin-polarized currents. Here, we demonstrate coherent driving of a single spin by a radiofrequency spin-polarized current injected from the tip of a scanning tunneling microscope into an organic molecule. With the excitation of electron paramagnetic resonance, we established dynamic control of single spins by spin torque using a local electric current. In addition, our work highlights the dissipative action of the spin-transfer torque, in contrast to the nondissipative action of the magnetic field, which allows for the manipulation of individual spins based on controlled decoherence.
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Affiliation(s)
- Stepan Kovarik
- Department of Materials, ETH Zurich, CH-8093 Zürich, Switzerland
| | - Richard Schlitz
- Department of Materials, ETH Zurich, CH-8093 Zürich, Switzerland
| | | | - Dominic Ruckert
- Department of Materials, ETH Zurich, CH-8093 Zürich, Switzerland
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4
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Pachlatko R, Prumbaum N, Krass MD, Grob U, Degen CL, Eichler A. Nanoscale Magnets Embedded in a Microstrip. NANO LETTERS 2024; 24:2081-2086. [PMID: 38300507 DOI: 10.1021/acs.nanolett.3c04818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2024]
Abstract
Nanoscale magnetic resonance imaging (NanoMRI) is an active area of applied research with potential applications in structural biology and quantum engineering. The success of this technological vision hinges on improving the instrument's sensitivity and functionality. A particular challenge is the optimization of the magnetic field gradient required for spatial encoding and of the radio frequency field used for spin control, in analogy to the components used in clinical MRI. In this work, we present the fabrication and characterization of a magnet-in-microstrip device that yields a compact form factor for both elements. We find that our design leads to a number of advantages, among them a 4-fold increase of the magnetic field gradient compared to those achieved with traditional fabrication methods. Our results can be useful for boosting the efficiency of a variety of different experimental arrangements and detection principles in the field of NanoMRI.
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Affiliation(s)
- Raphael Pachlatko
- Laboratory for Solid State Physics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Nils Prumbaum
- Laboratory for Solid State Physics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Marc-Dominik Krass
- Laboratory for Solid State Physics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Urs Grob
- Laboratory for Solid State Physics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Christian L Degen
- Laboratory for Solid State Physics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Alexander Eichler
- Laboratory for Solid State Physics, ETH Zurich, CH-8093 Zurich, Switzerland
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5
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Sellies L, Spachtholz R, Bleher S, Eckrich J, Scheuerer P, Repp J. Single-molecule electron spin resonance by means of atomic force microscopy. Nature 2023; 624:64-68. [PMID: 38057570 DOI: 10.1038/s41586-023-06754-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 10/17/2023] [Indexed: 12/08/2023]
Abstract
Understanding and controlling decoherence in open quantum systems is of fundamental interest in science, whereas achieving long coherence times is critical for quantum information processing1. Although great progress was made for individual systems, and electron spin resonance (ESR) of single spins with nanoscale resolution has been demonstrated2-4, the understanding of decoherence in many complex solid-state quantum systems requires ultimately controlling the environment down to atomic scales, as potentially enabled by scanning probe microscopy with its atomic and molecular characterization and manipulation capabilities. Consequently, the recent implementation of ESR in scanning tunnelling microscopy5-8 represents a milestone towards this goal and was quickly followed by the demonstration of coherent oscillations9,10 and access to nuclear spins11 with real-space atomic resolution. Atomic manipulation even fuelled the ambition to realize the first artificial atomic-scale quantum devices12. However, the current-based sensing inherent to this method limits coherence times12,13. Here we demonstrate pump-probe ESR atomic force microscopy (AFM) detection of electron spin transitions between non-equilibrium triplet states of individual pentacene molecules. Spectra of these transitions exhibit sub-nanoelectronvolt spectral resolution, allowing local discrimination of molecules that only differ in their isotopic configuration. Furthermore, the electron spins can be coherently manipulated over tens of microseconds. We anticipate that single-molecule ESR-AFM can be combined with atomic manipulation and characterization and thereby paves the way to learn about the atomistic origins of decoherence in atomically well-defined quantum elements and for fundamental quantum-sensing experiments.
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Affiliation(s)
- Lisanne Sellies
- Institute of Experimental and Applied Physics, University of Regensburg, Regensburg, Germany.
| | - Raffael Spachtholz
- Institute of Experimental and Applied Physics, University of Regensburg, Regensburg, Germany
| | - Sonja Bleher
- Institute of Experimental and Applied Physics, University of Regensburg, Regensburg, Germany
| | - Jakob Eckrich
- Institute of Experimental and Applied Physics, University of Regensburg, Regensburg, Germany
| | - Philipp Scheuerer
- Institute of Experimental and Applied Physics, University of Regensburg, Regensburg, Germany
| | - Jascha Repp
- Institute of Experimental and Applied Physics, University of Regensburg, Regensburg, Germany.
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6
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Tada K, Kawakami T, Hinuma Y. Model calculations for the prediction of the diradical character of physisorbed molecules: p-benzyne/MgO and p-benzyne/SrO. Phys Chem Chem Phys 2023; 25:29424-29436. [PMID: 37795574 DOI: 10.1039/d3cp02988c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/06/2023]
Abstract
The analysis of the diradical state of functional open-shell molecules is important for understanding their physical properties and chemical reactivity. The diradical character is an important factor in the functional elucidation and design of open-shell molecules. In recent years, attempts have been made to immobilise functional open-shell molecules on surfaces to form devices. However, the influence of surface interactions on the diradical state remains unclear. In this study, the physisorption structures of p-benzyne, which is a typical diradical molecule, on MgO(001) and SrO(001) surfaces are used as models to investigate how the diradical character is affected by physisorption. This is done using approximate spin-projected density functional theory calculations with dispersion correction and plane-wave basis (AP-DFT-D3/plane-wave calculations). The diradical character change (Δy) due to adsorption can be categorised into three factors, namely the change due to the distortion of the diradical molecule (Δydis), the interaction between neighbouring diradical molecules (Δycoh), and molecule-surface interactions (Δysurf). In all the calculated models, physisorption reduced the diradical character (Δy < 0), and the contribution of Δysurf was the largest among the three factors. The calculated results show that adsorption induces electron delocalisation to π-conjugated orbitals and intramolecular charge polarisation, both of which contribute to reducing the occupancy of singly occupied molecular orbitals. This indicates that the diradical character of p-benzyne is reduced by the stabilisation of the resonance structures. Furthermore, geometry optimisation of the surfaces shows that the chemical-soft surface (SrO) varies the diradical character more significantly than the chemical-hard surface (MgO). This study shows that the open-shell electronic state and stack structure of diradical molecules can be controlled through the analysis of the surface diradical state.
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Affiliation(s)
- Kohei Tada
- Research Institute of Electrochemical Energy (RIECEN), Department of Energy and Environment, National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577, Japan.
| | - Takashi Kawakami
- RIKEN Center for Computational Science, Kobe, Hyogo 650-0047, Japan
- Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Yoyo Hinuma
- Research Institute of Electrochemical Energy (RIECEN), Department of Energy and Environment, National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577, Japan.
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7
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Yin R, Wang Z, Tan S, Ma C, Wang B. On-Surface Synthesis of Graphene Nanoribbons with Atomically Precise Structural Heterogeneities and On-Site Characterizations. ACS NANO 2023; 17:17610-17623. [PMID: 37666005 DOI: 10.1021/acsnano.3c06128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/06/2023]
Abstract
Graphene nanoribbons (GNRs) are strips of graphene, with widths of a few nanometers, that are promising candidates for future applications in nanodevices and quantum information processing due to their highly tunable structure-dependent electronic, spintronic, topological, and optical properties. Implantation of periodic structural heterogeneities, such as heteroatoms, nanopores, and non-hexagonal rings, has become a powerful manner for tailoring the designer properties of GNRs. The bottom-up synthesis approach, by combining on-surface chemical reactions based on rationally designed molecular precursors and in situ tip-based microscopic and spectroscopic techniques, promotes the construction of atomically precise GNRs with periodic structural modulations. However, there are still obstacles and challenges lying on the way toward the understanding of the intrinsic structure-property relations, such as the strong screening and Fermi level pinning effect of the normally used transition metal substrates and the lack of collective tip-based techniques that can cover multi-internal degrees of freedom of the GNRs. In this Perspective, we briefly review the recent progress in the on-surface synthesis of GNRs with diverse structural heterogeneities and highlight the structure-property relations as characterized by the noncontact atomic force microscopy and scanning tunneling microscopy/spectroscopy. We furthermore motivate to deliver the need for developing strategies to achieve quasi-freestanding GNRs and for exploiting multifunctional tip-based techniques to collectively probe the intrinsic properties.
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Affiliation(s)
- Ruoting Yin
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, New Cornerstone Science Laboratory, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Zhengya Wang
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, New Cornerstone Science Laboratory, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Shijing Tan
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, New Cornerstone Science Laboratory, University of Science and Technology of China, Hefei, Anhui 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
| | - Chuanxu Ma
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, New Cornerstone Science Laboratory, University of Science and Technology of China, Hefei, Anhui 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
| | - Bing Wang
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, New Cornerstone Science Laboratory, University of Science and Technology of China, Hefei, Anhui 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
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8
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Zhang X, Reina-Gálvez J, Wolf C, Wang Y, Aubin H, Heinrich AJ, Choi T. Influence of the Magnetic Tip on Heterodimers in Electron Spin Resonance Combined with Scanning Tunneling Microscopy. ACS NANO 2023; 17:16935-16942. [PMID: 37643247 DOI: 10.1021/acsnano.3c04024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Investigating the quantum properties of individual spins adsorbed on surfaces by electron spin resonance combined with scanning tunneling microscopy (ESR-STM) has shown great potential for the development of quantum information technology on the atomic scale. A magnetic tip exhibiting high spin polarization is critical for performing an ESR-STM experiment. While the tip has been conventionally treated as providing a static magnetic field in ESR-STM, it was found that the tip can exhibit bistability, influencing ESR spectra. Ideally, the ESR splitting caused by the magnetic interaction between two spins on a surface should be independent of the tip. However, we found that the measured ESR splitting of a metal atom-molecule heterodimer can be tip-dependent. Detailed theoretical analysis reveals that this tip-dependent ESR splitting is caused by a different interaction energy between the tip and each spin of the heterodimer. Our work provides a comprehensive reference for characterizing tip features in ESR-STM experiments and highlights the importance of employing a proper physical model when describing the ESR tip, in particular, for heterospin systems.
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Affiliation(s)
- Xue Zhang
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Republic of Korea
- Ewha Womans University, Seoul 03760, Republic of Korea
- Spin-X Institute, School of Microelectronics, South China University of Technology, Guangzhou 511442, People's Republic of China
| | - Jose Reina-Gálvez
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Republic of Korea
- Ewha Womans University, Seoul 03760, Republic of Korea
| | - Christoph Wolf
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Republic of Korea
- Ewha Womans University, Seoul 03760, Republic of Korea
| | - Yu Wang
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Republic of Korea
- Ewha Womans University, Seoul 03760, Republic of Korea
| | - Hervé Aubin
- Universités Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, 91120 Palaiseau, France
| | - Andreas J Heinrich
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Republic of Korea
- Department of Physics, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Taeyoung Choi
- Department of Physics, Ewha Womans University, Seoul 03760, Republic of Korea
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9
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Hazan Z, Averbukh M, Manassen Y. ESR-STM on diamagnetic molecule: C 60 on graphene. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2023; 348:107377. [PMID: 36709618 DOI: 10.1016/j.jmr.2023.107377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 01/08/2023] [Accepted: 01/09/2023] [Indexed: 06/18/2023]
Abstract
Electron Spin Resonance-Scanning Tunneling Microscopy (ESR-STM) of C60 radical ion on graphene is a first demonstration of ESR-STM on diamagnetic molecules. ESR-STM signal at gaverage=2.0±0.1 was measured in accordance with macroscopic ESR of C60 radical ion. The ESR-STM signal was bias voltage dependent, as it reflects the charge state of the molecule. The signal appears in the bias voltage which enables the ionization of the lowest unoccupied molecular orbital (LUMO) - creation of radical anion, and the highest occupied molecular orbital (HOMO) - creation of a radical cation of the C60 molecule when it deposited on graphene. In parallel, ESR-STM signal at gaverage=1.7±0.1 was ascribed to Tungsten oxide (WO3) at the tip apex. In several experiments, triplet spectrum was observed, and we ascribed their origin to zero-field splitting of doubly ionized C120O-2 dimer, as argued in previous ESR experiments of C60 samples. Second possibility is hyperfine coupling with two 13C nuclei. In addition, we further validate the interference mechanism previously suggested for ESR-STM noise spectroscopy. The ability of ESR-STM to observe ESR of diamagnetic molecules in parallel with observing their electronic structure, provides a general single molecule identification technique.
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Affiliation(s)
- Zion Hazan
- Department of Physics, Ben Gurion University, P.O. Box 653, Beer Sheva 84105, Israel
| | - Michael Averbukh
- Department of Physics, Ben Gurion University, P.O. Box 653, Beer Sheva 84105, Israel
| | - Yishay Manassen
- Department of Physics, Ben Gurion University, P.O. Box 653, Beer Sheva 84105, Israel.
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10
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Salvadori E, Bruzzese PC, Giamello E, Chiesa M. Single Metal Atoms on Oxide Surfaces: Assessing the Chemical Bond through 17O Electron Paramagnetic Resonance. Acc Chem Res 2022; 55:3706-3715. [PMID: 36442497 PMCID: PMC9774661 DOI: 10.1021/acs.accounts.2c00606] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
ConspectusEven in the gas phase single atoms possess catalytic properties, which can be crucially enhanced and modulated by the chemical interaction with a solid support. This effect, known as electronic metal-support interaction, encompasses charge transfer, orbital overlap, coordination structure, etc., in other words, all the crucial features of the chemical bond. These very features are the object of this Account, with specific reference to open-shell (paramagnetic) single metal atoms or ions on oxide supports. Such atomically dispersed species are part of the emerging class of heterogeneous catalysts known as single-atom catalysts (SACs). In these materials, atomic dispersion ensures maximum atom utilization and uniform active sites, whereby the nature of the chemical interaction between the metal and the oxide surface modulates the catalytic activity of the metal active site by tuning the energy of the frontier orbitals. A comprehensive set of examples includes fourth period metal atoms and ions in zeolites on insulating (e.g., MgO) or reducible (e.g., TiO2) oxides and are among the most relevant catalysts for a wealth of key processes of industrial and environmental relevance, from the abatement of NOx to the selective oxidation of hydrocarbons and the conversion of methane to methanol.There exist several spectroscopic techniques able to inform on the geometric and electronic structure of isolated single metal ion sites, but either they yield information averaged over the bulk or they lack description of the intimate features of chemical bonding, which include covalency, ionicity, electron and spin delocalization. All of these can be recovered at once by measuring the magnetic interactions between open-shell metals and the surrounding nuclei with Electron Paramagnetic Resonance (EPR) spectroscopy. In the case of oxides, this entails the synthesis of 17O isotopically enriched materials. We have established 17O EPR as a unique source of information about the local binding environment around oxygen of magnetic atoms or ions on different oxidic supports to rationalize structure-property relationships. Here, we will describe strategies for 17O surface enrichments and approaches to monitor the state of charge and spin delocalization of atoms or ions from K to Zn dispersed on oxide surfaces characterized by different chemical properties (i.e., basicity or reducibility). Emphasis is placed on chemical insight at the atomic-scale level achieved by 17O EPR, which is a crucial step in understanding the structure-property relationships of single metal atom catalysts and in enabling efficient design of future materials for a range of end uses.
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Affiliation(s)
- Enrico Salvadori
- Department
of Chemistry and NIS Centre of Excellence, University of Turin, via Giuria 9, 10125 Torino, Italy
| | - Paolo Cleto Bruzzese
- Department
of Chemistry and NIS Centre of Excellence, University of Turin, via Giuria 9, 10125 Torino, Italy,Felix
Bloch Institute for Solid State Physics, Leipzig University, Linnéstr. 5, 04103 Leipzig, Germany
| | - Elio Giamello
- Department
of Chemistry and NIS Centre of Excellence, University of Turin, via Giuria 9, 10125 Torino, Italy
| | - Mario Chiesa
- Department
of Chemistry and NIS Centre of Excellence, University of Turin, via Giuria 9, 10125 Torino, Italy,E-mail:
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11
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Kim J, Noh K, Chen Y, Donati F, Heinrich AJ, Wolf C, Bae Y. Anisotropic Hyperfine Interaction of Surface-Adsorbed Single Atoms. NANO LETTERS 2022; 22:9766-9772. [PMID: 36317830 PMCID: PMC9756343 DOI: 10.1021/acs.nanolett.2c02782] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 10/20/2022] [Indexed: 06/16/2023]
Abstract
Hyperfine interactions have been widely used in material science, organic chemistry, and structural biology as a sensitive probe to local chemical environments. However, traditional ensemble measurements of hyperfine interactions average over a macroscopic number of spins with different geometrical locations and nuclear isotopes. Here, we use a scanning tunneling microscope (STM) combined with electron spin resonance (ESR) to measure hyperfine spectra of hydrogenated-Ti on MgO/Ag(100) at low-symmetry binding sites and thereby determine the isotropic and anisotropic hyperfine interactions at the single-atom level. Combining vector-field ESR spectroscopy with STM-based atom manipulation, we characterize the full hyperfine tensors of 47Ti and 49Ti and identify significant spatial anisotropy of the hyperfine interactions for both isotopes. Density functional theory calculations reveal that the large hyperfine anisotropy arises from highly anisotropic distributions of the ground-state electron spin density. Our work highlights the power of ESR-STM-enabled single-atom hyperfine spectroscopy in revealing electronic ground states and atomic-scale chemical environments.
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Affiliation(s)
- Jinkyung Kim
- Center
for Quantum Nanoscience (QNS), Institute
for Basic Science (IBS), Seoul 03760, South Korea
- Department
of Physics, Ewha Womans University, Seoul 03760, South Korea
| | - Kyungju Noh
- Center
for Quantum Nanoscience (QNS), Institute
for Basic Science (IBS), Seoul 03760, South Korea
- Department
of Physics, Ewha Womans University, Seoul 03760, South Korea
| | - Yi Chen
- Center
for Quantum Nanoscience (QNS), Institute
for Basic Science (IBS), Seoul 03760, South Korea
- Ewha
Womans University, Seoul 03760, Republic of Korea
| | - Fabio Donati
- Center
for Quantum Nanoscience (QNS), Institute
for Basic Science (IBS), Seoul 03760, South Korea
- Department
of Physics, Ewha Womans University, Seoul 03760, South Korea
| | - Andreas J. Heinrich
- Center
for Quantum Nanoscience (QNS), Institute
for Basic Science (IBS), Seoul 03760, South Korea
- Department
of Physics, Ewha Womans University, Seoul 03760, South Korea
| | - Christoph Wolf
- Center
for Quantum Nanoscience (QNS), Institute
for Basic Science (IBS), Seoul 03760, South Korea
- Ewha
Womans University, Seoul 03760, Republic of Korea
| | - Yujeong Bae
- Center
for Quantum Nanoscience (QNS), Institute
for Basic Science (IBS), Seoul 03760, South Korea
- Department
of Physics, Ewha Womans University, Seoul 03760, South Korea
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12
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Farinacci L, Veldman LM, Willke P, Otte S. Experimental Determination of a Single Atom Ground State Orbital through Hyperfine Anisotropy. NANO LETTERS 2022; 22:8470-8474. [PMID: 36305860 PMCID: PMC9650725 DOI: 10.1021/acs.nanolett.2c02783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 10/25/2022] [Indexed: 06/16/2023]
Abstract
Historically, electron spin resonance (ESR) has provided excellent insight into the electronic, magnetic, and chemical structure of samples hosting spin centers. In particular, the hyperfine interaction between the electron and the nuclear spins yields valuable structural information about these centers. In recent years, the combination of ESR and scanning tunneling microscopy (ESR-STM) has allowed to acquire such information about individual spin centers of magnetic atoms bound atop a surface, while additionally providing spatial information about the binding site. Here, we conduct a full angle-dependent investigation of the hyperfine splitting for individual hydrogenated titanium atoms on MgO/Ag(001) by measurements in a vector magnetic field. We observe strong anisotropy in both the g factor and the hyperfine tensor. Combining the results of the hyperfine splitting with the symmetry properties of the binding site obtained from STM images and a basic point charge model allows us to predict the shape of the electronic ground state configuration of the titanium atom. Relying on experimental values only, this method paves the way for a new protocol for electronic structure analysis for spin centers on surfaces.
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Affiliation(s)
- Laëtitia Farinacci
- Department
of Quantum Nanoscience, Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJDelft, The Netherlands
| | - Lukas M. Veldman
- Department
of Quantum Nanoscience, Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJDelft, The Netherlands
| | - Philip Willke
- Physikalisches
Institut, Karlsruhe Institute of Technology, 76131Karlsruhe, Germany
| | - Sander Otte
- Department
of Quantum Nanoscience, Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJDelft, The Netherlands
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13
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Shehada S, Dos Santos Dias M, Abusaa M, Lounis S. Interplay of magnetic states and hyperfine fields of iron dimers on MgO(001). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:385802. [PMID: 35835084 DOI: 10.1088/1361-648x/ac8135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 07/14/2022] [Indexed: 06/15/2023]
Abstract
Individual nuclear spin states can have very long lifetimes and could be useful as qubits. Progress in this direction was achieved on MgO/Ag(001) via detection of the hyperfine interaction (HFI) of Fe, Ti and Cu adatoms using scanning tunneling microscopy. Previously, we systematically quantified from first-principles the HFI for the whole series of 3d transition adatoms (Sc-Cu) deposited on various ultra-thin insulators, establishing the trends of the computed HFI with respect to the filling of the magnetic s- and d-orbitals of the adatoms and on the bonding with the substrate. Here we explore the case of dimers by investigating the correlation between the HFI and the magnetic state of free standing Fe dimers, single Fe adatoms and dimers deposited on a bilayer of MgO(001). We find that the magnitude of the HFI can be controlled by switching the magnetic state of the dimers. For short Fe-Fe distances, the antiferromagnetic state enhances the HFI with respect to that of the ferromagnetic state. By increasing the distance between the magnetic atoms, a transition toward the opposite behavior is observed. Furthermore, we demonstrate the ability to substantially modify the HFI by atomic control of the location of the adatoms on the substrate. Our results establish the limits of applicability of the usual hyperfine hamiltonian and we propose an extension based on multiple scattering processes.
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Affiliation(s)
- Sufyan Shehada
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich & JARA, 52425 Jülich, Germany
- Department of Physics, RWTH Aachen University, 52056 Aachen, Germany
- Department of Physics, Arab American University, Jenin, Palestine
| | - Manuel Dos Santos Dias
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich & JARA, 52425 Jülich, Germany
- Faculty of Physics, University of Duisburg-Essen & CENIDE, 47053 Duisburg, Germany
| | - Muayad Abusaa
- Department of Physics, Arab American University, Jenin, Palestine
| | - Samir Lounis
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich & JARA, 52425 Jülich, Germany
- Faculty of Physics, University of Duisburg-Essen & CENIDE, 47053 Duisburg, Germany
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14
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Tosoni S, Pacchioni G. Magnetic nature and hyperfine interactions of transition metal atoms adsorbed on ultrathin insulating films: a challenge for DFT. Phys Chem Chem Phys 2022; 24:15891-15903. [PMID: 35762384 DOI: 10.1039/d2cp01224c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The magnetic ground state and the hyperfine coupling parameters of some first-row transition metal (TM) atoms (Ti, Cr, Mn, Fe, Co, and Ni) adsorbed on ultrathin insulating oxide films are studied by means of DFT calculations. The results obtained using GGA, screened hybrid, and GGA+U functionals are compared for TMs adsorbed on free-standing MgO(100). Then, the case of adsorption on MgO mono- and bilayers supported on Ag(100) is studied using GGA+U. Along with the problematic aspects inherent to the calculation of hyperfine coupling constants, a critical dependence on the magnetic state and electron configuration of the TM is reported, which implies a real challenge for the state-of-the-art DFT methods. In the cases where all functionals considered provide a coherent magnetic and electron configuration, however, the calculated hyperfine parameters do not depend significantly on the choice of the functional. In this respect, the role of the metal support in the hyperfine coupling constants is highly system-dependent and becomes crucial in all cases where the support modifies the oxidation state of the adatom, induces a change in the bonding site or simply induces a rearrangement of the orbital energy diagram. This has important implications for the modelling of single TM atoms deposited on insulating ultrathin films supported on metals for application in quantum technologies or as memory devices.
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Affiliation(s)
- Sergio Tosoni
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Via Roberto Cozzi 55, 20125 Milan, Italy.
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Via Roberto Cozzi 55, 20125 Milan, Italy.
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15
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Osiecki JR, Suto S, Chutia A. Periodic corner holes on the Si(111)-7×7 surface can trap silver atoms. Nat Commun 2022; 13:2973. [PMID: 35624114 PMCID: PMC9142567 DOI: 10.1038/s41467-022-29768-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 03/29/2022] [Indexed: 11/09/2022] Open
Abstract
Advancement in nanotechnology to a large extent depends on the ability to manipulate materials at the atomistic level, including positioning single atoms on the active sites of the surfaces of interest, promoting strong chemical bonding. Here, we report a long-time confinement of a single Ag atom inside a corner hole (CH) of the technologically relevant Si(111)-7×7 surface, which has comparable size as a fullerene C60 molecule with a single dangling bond at the bottom center. Experiments reveal that a set of 17 Ag atoms stays entrapped in the CH for the entire duration of experiment, 4 days and 7 h. Warming up the surface to about 150 °C degrees forces the Ag atoms out of the CH within a few minutes. The processes of entrapment and diffusion are temperature dependent. Theoretical calculations based on density functional theory support the experimental results confirming the highest adsorption energy at the CH for the Ag atom, and suggest that other elements such as Li, Na, Cu, Au, F and I may display similar behavior. The capability of atomic manipulation at room temperature makes this effect particularly attractive for building single atom devices and possibly developing new engineering and nano-manufacturing methods. Positioning and trapping single atoms at specific sites of surfaces is a challenging goal that can advance the development of single atom devices. Here the authors demonstrate that single Ag atoms are trapped inside corner holes of the Si(111)-7×7 surface for more than 4 days at room temperature, and suggest that this behavior may be shared by other elements.
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Affiliation(s)
- Jacek R Osiecki
- MAX IV Laboratory, Lund University, SE22100, Lund, Sweden. .,Department of Physics, Tohoku University, Sendai, 980-8578, Japan.
| | - Shozo Suto
- Department of Physics, Tohoku University, Sendai, 980-8578, Japan.
| | - Arunabhiram Chutia
- School of Chemistry, University of Lincoln, Brayford Pool, Lincoln, LN6 7TS, United Kingdom.
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16
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Kovarik S, Robles R, Schlitz R, Seifert TS, Lorente N, Gambardella P, Stepanow S. Electron Paramagnetic Resonance of Alkali Metal Atoms and Dimers on Ultrathin MgO. NANO LETTERS 2022; 22:4176-4181. [PMID: 35512394 DOI: 10.1021/acs.nanolett.2c00980] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Electron paramagnetic resonance (EPR) can provide unique insight into the chemical structure and magnetic properties of dopants in oxide and semiconducting materials that are of interest for applications in electronics, catalysis, and quantum sensing. Here, we demonstrate that EPR in combination with scanning tunneling microscopy (STM) allows for probing the bonding and charge state of alkali metal atoms on an ultrathin magnesium oxide layer on a Ag substrate. We observe a magnetic moment of 1 μB for Li2, LiNa, and Na2 dimers corresponding to spin radicals with a charge state of +1e. Single alkali atoms have the same charge state and no magnetic moment. The ionization of the adsorbates is attributed to charge transfer through the oxide to the metal substrate. Our work highlights the potential of EPR-STM to provide insight into dopant atoms that are relevant for the control of the electrical properties of surfaces and nanodevices.
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Affiliation(s)
- Stepan Kovarik
- Department of Materials, ETH Zurich, Hönggerbergring 64, Zürich CH-8093, Switzerland
| | - Roberto Robles
- Centro de Física de Materiales CFM/MPC (CSIC-UPV/EHU), Paseo Manuel de Lardizabal 5, San Sebastián 20018, Spain
| | - Richard Schlitz
- Department of Materials, ETH Zurich, Hönggerbergring 64, Zürich CH-8093, Switzerland
| | - Tom Sebastian Seifert
- Department of Materials, ETH Zurich, Hönggerbergring 64, Zürich CH-8093, Switzerland
- Department of Physics, Freie Universität Berlin, Berlin 14195, Germany
| | - Nicolas Lorente
- Centro de Física de Materiales CFM/MPC (CSIC-UPV/EHU), Paseo Manuel de Lardizabal 5, San Sebastián 20018, Spain
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, San Sebastián 20018, Spain
| | - Pietro Gambardella
- Department of Materials, ETH Zurich, Hönggerbergring 64, Zürich CH-8093, Switzerland
| | - Sebastian Stepanow
- Department of Materials, ETH Zurich, Hönggerbergring 64, Zürich CH-8093, Switzerland
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17
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Chen Y, Bae Y, Heinrich AJ. Harnessing the Quantum Behavior of Spins on Surfaces. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022:e2107534. [PMID: 34994026 DOI: 10.1002/adma.202107534] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 12/28/2021] [Indexed: 06/14/2023]
Abstract
The desire to control and measure individual quantum systems such as atoms and ions in a vacuum has led to significant scientific and engineering developments in the past decades that form the basis of today's quantum information science. Single atoms and molecules on surfaces, on the other hand, are heavily investigated by physicists, chemists, and material scientists in search of novel electronic and magnetic functionalities. These two paths crossed in 2015 when it was first clearly demonstrated that individual spins on a surface can be coherently controlled and read out in an all-electrical fashion. The enabling technique is a combination of scanning tunneling microscopy (STM) and electron spin resonance, which offers unprecedented coherent controllability at the Angstrom length scale. This review aims to illustrate the essential ingredients that allow the quantum operations of single spins on surfaces. Three domains of applications of surface spins, namely quantum sensing, quantum control, and quantum simulation, are discussed with physical principles explained and examples presented. Enabled by the atomically-precise fabrication capability of STM, single spins on surfaces might one day lead to the realization of quantum nanodevices and artificial quantum materials at the atomic scale.
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Affiliation(s)
- Yi Chen
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul, 03760, Korea
- Department of Physics, Ewha Womans University, Seoul, 03760, Korea
| | - Yujeong Bae
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul, 03760, Korea
- Department of Physics, Ewha Womans University, Seoul, 03760, Korea
| | - Andreas J Heinrich
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul, 03760, Korea
- Department of Physics, Ewha Womans University, Seoul, 03760, Korea
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18
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Eom D, Koo JY. Intraband Spin-Dependent Recombination of Bound Holes in Silicon. PHYSICAL REVIEW LETTERS 2021; 127:256801. [PMID: 35029440 DOI: 10.1103/physrevlett.127.256801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 11/24/2021] [Indexed: 06/14/2023]
Abstract
We generate paramagnetic centers on a heavily boron-doped Si(111) surface by using a scanning tunneling microscope and show that they mediate the spin-dependent recombination of the bound holes of the boron acceptor via direct visualization. This recombination is the intraband process and is significantly affected by the spin-orbit coupling effect. We also demonstrate that such a paramagnetic center with a boron acceptor at its neighbor site can be produced with atomic precision, which makes it a promising candidate for implementing position-controlled impurity qubits with an electrical readout mechanism in silicon.
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Affiliation(s)
- Daejin Eom
- Korea Research Institute of Standards and Science, Yuseong, Daejeon 34113, Republic of Korea
| | - Ja-Yong Koo
- Korea Research Institute of Standards and Science, Yuseong, Daejeon 34113, Republic of Korea
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19
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Zhang X, Wolf C, Wang Y, Aubin H, Bilgeri T, Willke P, Heinrich AJ, Choi T. Electron spin resonance of single iron phthalocyanine molecules and role of their non-localized spins in magnetic interactions. Nat Chem 2021; 14:59-65. [PMID: 34764471 DOI: 10.1038/s41557-021-00827-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 09/27/2021] [Indexed: 11/09/2022]
Abstract
Electron spin resonance (ESR) spectroscopy is a crucial tool, through spin labelling, in investigations of the chemical structure of materials and of the electronic structure of materials associated with unpaired spins. ESR spectra measured in molecular systems, however, are established on large ensembles of spins and usually require a complicated structural analysis. Recently, the combination of scanning tunnelling microscopy with ESR has proved to be a powerful tool to image and coherently control individual atomic spins on surfaces. Here we extend this technique to single coordination complexes-iron phthalocyanines (FePc)-and investigate the magnetic interactions between their molecular spin with either another molecular spin (in FePc-FePc dimers) or an atomic spin (in FePc-Ti pairs). We show that the molecular spin density of FePc is both localized at the central Fe atom and also distributed to the ligands (Pc), which yields a strongly molecular-geometry-dependent exchange coupling.
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Affiliation(s)
- Xue Zhang
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul, Republic of Korea.,Ewha Womans University, Seoul, Republic of Korea
| | - Christoph Wolf
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul, Republic of Korea.,Ewha Womans University, Seoul, Republic of Korea
| | - Yu Wang
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul, Republic of Korea.,Ewha Womans University, Seoul, Republic of Korea
| | - Hervé Aubin
- Universités Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, Palaiseau, France
| | - Tobias Bilgeri
- Institute of Physics, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Philip Willke
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul, Republic of Korea.,Ewha Womans University, Seoul, Republic of Korea.,Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Andreas J Heinrich
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul, Republic of Korea. .,Department of Physics, Ewha Womans University, Seoul, Republic of Korea.
| | - Taeyoung Choi
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul, Republic of Korea. .,Department of Physics, Ewha Womans University, Seoul, Republic of Korea.
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20
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Peng J, Sokolov S, Hernangómez-Pérez D, Evers F, Gross L, Lupton JM, Repp J. Atomically resolved single-molecule triplet quenching. Science 2021; 373:452-456. [PMID: 34437120 DOI: 10.1126/science.abh1155] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Accepted: 05/25/2021] [Indexed: 01/14/2023]
Abstract
The nonequilibrium triplet state of molecules plays an important role in photocatalysis, organic photovoltaics, and photodynamic therapy. We report the direct measurement of the triplet lifetime of an individual pentacene molecule on an insulating surface with atomic resolution by introducing an electronic pump-probe method in atomic force microscopy. Strong quenching of the triplet lifetime is observed if oxygen molecules are coadsorbed in close proximity. By means of single-molecule manipulation techniques, different arrangements with oxygen molecules were created and characterized with atomic precision, allowing for the direct correlation of molecular arrangements with the lifetime of the quenched triplet. Such electrical addressing of long-lived triplets of single molecules, combined with atomic-scale manipulation, offers previously unexplored routes to control and study local spin-spin interactions.
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Affiliation(s)
- Jinbo Peng
- Institute for Experimental and Applied Physics and Regensburg Center for Ultrafast Nanoscopy (RUN), University of Regensburg, 93040 Regensburg, Germany.
| | - Sophia Sokolov
- Institute for Experimental and Applied Physics and Regensburg Center for Ultrafast Nanoscopy (RUN), University of Regensburg, 93040 Regensburg, Germany
| | - Daniel Hernangómez-Pérez
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Ferdinand Evers
- Institute for Theoretical Physics, University of Regensburg, 93040 Regensburg, Germany
| | - Leo Gross
- IBM Research-Zurich, 8803 Rüschlikon, Switzerland
| | - John M Lupton
- Institute for Experimental and Applied Physics and Regensburg Center for Ultrafast Nanoscopy (RUN), University of Regensburg, 93040 Regensburg, Germany
| | - Jascha Repp
- Institute for Experimental and Applied Physics and Regensburg Center for Ultrafast Nanoscopy (RUN), University of Regensburg, 93040 Regensburg, Germany.
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21
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Veldman LM, Farinacci L, Rejali R, Broekhoven R, Gobeil J, Coffey D, Ternes M, Otte AF. Free coherent evolution of a coupled atomic spin system initialized by electron scattering. Science 2021; 372:964-968. [PMID: 34045351 DOI: 10.1126/science.abg8223] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 02/19/2021] [Accepted: 04/23/2021] [Indexed: 11/02/2022]
Abstract
Full insight into the dynamics of a coupled quantum system depends on the ability to follow the effect of a local excitation in real-time. Here, we trace the free coherent evolution of a pair of coupled atomic spins by means of scanning tunneling microscopy. Rather than using microwave pulses, we use a direct-current pump-probe scheme to detect the local magnetization after a current-induced excitation performed on one of the spins. By making use of magnetic interaction with the probe tip, we are able to tune the relative precession of the spins. We show that only if their Larmor frequencies match, the two spins can entangle, causing angular momentum to be swapped back and forth. These results provide insight into the locality of electron spin scattering and set the stage for controlled migration of a quantum state through an extended spin lattice.
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Affiliation(s)
- Lukas M Veldman
- Department of Quantum Nanoscience, Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, the Netherlands
| | - Laëtitia Farinacci
- Department of Quantum Nanoscience, Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, the Netherlands
| | - Rasa Rejali
- Department of Quantum Nanoscience, Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, the Netherlands
| | - Rik Broekhoven
- Department of Quantum Nanoscience, Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, the Netherlands
| | - Jérémie Gobeil
- Department of Quantum Nanoscience, Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, the Netherlands
| | - David Coffey
- Department of Quantum Nanoscience, Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, the Netherlands
| | - Markus Ternes
- RWTH Aachen University, Institute of Physics, D-52074 Aachen, Germany.,Peter-Grünberg-Institute, Forschungszentrum Jülich, D-52425 Jülich, Germany
| | - Alexander F Otte
- Department of Quantum Nanoscience, Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, the Netherlands.
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22
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Bian K, Gerber C, Heinrich AJ, Müller DJ, Scheuring S, Jiang Y. Scanning probe microscopy. ACTA ACUST UNITED AC 2021. [DOI: 10.1038/s43586-021-00033-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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23
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van Weerdenburg WMJ, Steinbrecher M, van Mullekom NPE, Gerritsen JW, von Allwörden H, Natterer FD, Khajetoorians AA. A scanning tunneling microscope capable of electron spin resonance and pump-probe spectroscopy at mK temperature and in vector magnetic field. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:033906. [PMID: 33820009 DOI: 10.1063/5.0040011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 02/19/2021] [Indexed: 06/12/2023]
Abstract
In the last decade, detecting spin dynamics at the atomic scale has been enabled by combining techniques such as electron spin resonance (ESR) or pump-probe spectroscopy with scanning tunneling microscopy (STM). Here, we demonstrate an ultra-high vacuum STM operational at milliKelvin (mK) temperatures and in a vector magnetic field capable of both ESR and pump-probe spectroscopy. By implementing GHz compatible cabling, we achieve appreciable RF amplitudes at the junction while maintaining the mK base temperature and high energy resolution. We demonstrate the successful operation of our setup by utilizing two experimental ESR modes (frequency sweep and magnetic field sweep) on an individual TiH molecule on MgO/Ag(100) and extract the effective g-factor. We trace the ESR transitions down to MHz into an unprecedented low frequency band enabled by the mK base temperature. We also implement an all-electrical pump-probe scheme based on waveform sequencing suited for studying dynamics down to the nanoseconds range. We benchmark our system by detecting the spin relaxation time T1 of individual Fe atoms on MgO/Ag(100) and note a field strength and orientation dependent relaxation time.
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Affiliation(s)
| | - Manuel Steinbrecher
- Institute for Molecules and Materials, Radboud University, 6525 AJ Nijmegen, The Netherlands
| | - Niels P E van Mullekom
- Institute for Molecules and Materials, Radboud University, 6525 AJ Nijmegen, The Netherlands
| | - Jan W Gerritsen
- Institute for Molecules and Materials, Radboud University, 6525 AJ Nijmegen, The Netherlands
| | - Henning von Allwörden
- Institute for Molecules and Materials, Radboud University, 6525 AJ Nijmegen, The Netherlands
| | - Fabian D Natterer
- Department of Physics, University of Zurich, CH-8057 Zurich, Switzerland
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24
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McMillan SR, Harmon NJ, Flatté ME. Image of Dynamic Local Exchange Interactions in the dc Magnetoresistance of Spin-Polarized Current through a Dopant. PHYSICAL REVIEW LETTERS 2020; 125:257203. [PMID: 33416385 DOI: 10.1103/physrevlett.125.257203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 09/15/2020] [Accepted: 11/10/2020] [Indexed: 06/12/2023]
Abstract
We predict strong, dynamical effects in the dc magnetoresistance of current flowing from a spin-polarized electrical contact through a magnetic dopant in a nonmagnetic host. Using the stochastic Liouville formalism we calculate clearly defined resonances in the dc magnetoresistance when the applied magnetic field matches the exchange interaction with a nearby spin. At these resonances spin precession in the applied magnetic field is canceled by spin evolution in the exchange field, preserving a dynamic bottleneck for spin transport through the dopant. Similar features emerge when the dopant spin is coupled to nearby nuclei through the hyperfine interaction. These features provide a precise means of measuring exchange or hyperfine couplings between localized spins near a surface using spin-polarized scanning tunneling microscopy, without any ac electric or magnetic fields, even when the exchange or hyperfine energy is orders of magnitude smaller than the thermal energy.
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Affiliation(s)
- Stephen R McMillan
- Optical Science and Technology Center, and Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242, USA
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
| | - Nicholas J Harmon
- Optical Science and Technology Center, and Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242, USA
| | - Michael E Flatté
- Optical Science and Technology Center, and Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242, USA
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
- Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, Netherlands
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25
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Seifert TS, Kovarik S, Juraschek DM, Spaldin NA, Gambardella P, Stepanow S. Longitudinal and transverse electron paramagnetic resonance in a scanning tunneling microscope. SCIENCE ADVANCES 2020; 6:eabc5511. [PMID: 32998882 PMCID: PMC7527223 DOI: 10.1126/sciadv.abc5511] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 08/13/2020] [Indexed: 06/11/2023]
Abstract
Electron paramagnetic resonance (EPR) spectroscopy is widely used to characterize paramagnetic complexes. Recently, EPR combined with scanning tunneling microscopy (STM) achieved single-spin sensitivity with sub-angstrom spatial resolution. The excitation mechanism of EPR in STM, however, is broadly debated, raising concerns about widespread application of this technique. We present an extensive experimental study and modeling of EPR-STM of Fe and hydrogenated Ti atoms on a MgO surface. Our results support a piezoelectric coupling mechanism, in which the EPR species oscillate adiabatically in the inhomogeneous magnetic field of the STM tip. An analysis based on Bloch equations combined with atomic-multiplet calculations identifies different EPR driving forces. Specifically, transverse magnetic field gradients drive the spin-1/2 hydrogenated Ti, whereas longitudinal magnetic field gradients drive the spin-2 Fe. Also, our results highlight the potential of piezoelectric coupling to induce electric dipole moments, thereby broadening the scope of EPR-STM to nonpolar species and nonlinear excitation schemes.
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Affiliation(s)
- Tom S Seifert
- Department of Materials, ETH Zürich, 8093 Zürich, Switzerland.
| | - Stepan Kovarik
- Department of Materials, ETH Zürich, 8093 Zürich, Switzerland
| | - Dominik M Juraschek
- Department of Materials, ETH Zürich, 8093 Zürich, Switzerland
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
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26
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Asaad S, Mourik V, Joecker B, Johnson MAI, Baczewski AD, Firgau HR, Mądzik MT, Schmitt V, Pla JJ, Hudson FE, Itoh KM, McCallum JC, Dzurak AS, Laucht A, Morello A. Coherent electrical control of a single high-spin nucleus in silicon. Nature 2020; 579:205-209. [PMID: 32161384 DOI: 10.1038/s41586-020-2057-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 01/30/2020] [Indexed: 11/09/2022]
Abstract
Nuclear spins are highly coherent quantum objects. In large ensembles, their control and detection via magnetic resonance is widely exploited, for example, in chemistry, medicine, materials science and mining. Nuclear spins also featured in early proposals for solid-state quantum computers1 and demonstrations of quantum search2 and factoring3 algorithms. Scaling up such concepts requires controlling individual nuclei, which can be detected when coupled to an electron4-6. However, the need to address the nuclei via oscillating magnetic fields complicates their integration in multi-spin nanoscale devices, because the field cannot be localized or screened. Control via electric fields would resolve this problem, but previous methods7-9 relied on transducing electric signals into magnetic fields via the electron-nuclear hyperfine interaction, which severely affects nuclear coherence. Here we demonstrate the coherent quantum control of a single 123Sb (spin-7/2) nucleus using localized electric fields produced within a silicon nanoelectronic device. The method exploits an idea proposed in 196110 but not previously realized experimentally with a single nucleus. Our results are quantitatively supported by a microscopic theoretical model that reveals how the purely electrical modulation of the nuclear electric quadrupole interaction results in coherent nuclear spin transitions that are uniquely addressable owing to lattice strain. The spin dephasing time, 0.1 seconds, is orders of magnitude longer than those obtained by methods that require a coupled electron spin to achieve electrical driving. These results show that high-spin quadrupolar nuclei could be deployed as chaotic models, strain sensors and hybrid spin-mechanical quantum systems using all-electrical controls. Integrating electrically controllable nuclei with quantum dots11,12 could pave the way to scalable, nuclear- and electron-spin-based quantum computers in silicon that operate without the need for oscillating magnetic fields.
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Affiliation(s)
- Serwan Asaad
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, New South Wales, Australia
| | - Vincent Mourik
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, New South Wales, Australia
| | - Benjamin Joecker
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, New South Wales, Australia
| | - Mark A I Johnson
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, New South Wales, Australia
| | - Andrew D Baczewski
- Center for Computing Research, Sandia National Laboratories, Albuquerque, NM, USA
| | - Hannes R Firgau
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, New South Wales, Australia
| | - Mateusz T Mądzik
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, New South Wales, Australia
| | - Vivien Schmitt
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, New South Wales, Australia
| | - Jarryd J Pla
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, New South Wales, Australia
| | - Fay E Hudson
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, New South Wales, Australia
| | - Kohei M Itoh
- School of Fundamental Science and Technology, Keio University, Yokohama, Japan
| | - Jeffrey C McCallum
- Centre for Quantum Computation and Communication Technology, School of Physics, University of Melbourne, Melbourne, Victoria, Australia
| | - Andrew S Dzurak
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, New South Wales, Australia
| | - Arne Laucht
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, New South Wales, Australia
| | - Andrea Morello
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, New South Wales, Australia.
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27
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Willke P, Singha A, Zhang X, Esat T, Lutz CP, Heinrich AJ, Choi T. Tuning Single-Atom Electron Spin Resonance in a Vector Magnetic Field. NANO LETTERS 2019; 19:8201-8206. [PMID: 31661282 DOI: 10.1021/acs.nanolett.9b03559] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Spin resonance of single spin centers bears great potential for chemical structure analysis, quantum sensing, and quantum coherent manipulation. Essential for these experiments is the presence of a two-level spin system whose energy splitting can be chosen by applying a magnetic field. In recent years, a combination of electron spin resonance (ESR) and scanning tunneling microscopy (STM) has been demonstrated as a technique to detect magnetic properties of single atoms on surfaces and to achieve sub-microelectronvolts energy resolution. Nevertheless, up to now the role of the required magnetic fields has not been elucidated. Here, we perform single-atom ESR on individual Fe atoms adsorbed on magnesium oxide (MgO) using a two-dimensional vector magnetic field as well as the local field of the magnetic STM tip in a commercially available STM. We show how the ESR amplitude can be greatly improved by optimizing the magnetic fields, revealing in particular an enhanced signal at large in-plane magnetic fields. Moreover, we demonstrate that the stray field from the magnetic STM tip is a versatile tool. We use it here to drive the electron spin more efficiently and to perform ESR measurements at constant frequency by employing tip-field sweeps. Lastly, we show that it is possible to perform ESR using only the tip field, under zero external magnetic field, which promises to make this technique available in many existing STM systems.
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Affiliation(s)
- Philip Willke
- Center for Quantum Nanoscience , Institute for Basic Science (IBS) , Seoul 03760 , Republic of Korea
- Ewha Womans University , Seoul 03760 , Republic of Korea
| | - Aparajita Singha
- Center for Quantum Nanoscience , Institute for Basic Science (IBS) , Seoul 03760 , Republic of Korea
- Ewha Womans University , Seoul 03760 , Republic of Korea
| | - Xue Zhang
- Center for Quantum Nanoscience , Institute for Basic Science (IBS) , Seoul 03760 , Republic of Korea
- Ewha Womans University , Seoul 03760 , Republic of Korea
| | - Taner Esat
- Center for Quantum Nanoscience , Institute for Basic Science (IBS) , Seoul 03760 , Republic of Korea
- Ewha Womans University , Seoul 03760 , Republic of Korea
| | | | - Andreas J Heinrich
- Center for Quantum Nanoscience , Institute for Basic Science (IBS) , Seoul 03760 , Republic of Korea
- Department of Physics , Ewha Womans University , Seoul 03760 , Republic of Korea
| | - Taeyoung Choi
- Center for Quantum Nanoscience , Institute for Basic Science (IBS) , Seoul 03760 , Republic of Korea
- Department of Physics , Ewha Womans University , Seoul 03760 , Republic of Korea
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28
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Verlhac B, Bachellier N, Garnier L, Ormaza M, Abufager P, Robles R, Bocquet ML, Ternes M, Lorente N, Limot L. Atomic-scale spin sensing with a single molecule at the apex of a scanning tunneling microscope. Science 2019; 366:623-627. [DOI: 10.1126/science.aax8222] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 10/08/2019] [Indexed: 11/03/2022]
Affiliation(s)
- B. Verlhac
- Université de Strasbourg, CNRS, IPCMS, UMR 7504, F-67000 Strasbourg, France
| | - N. Bachellier
- Université de Strasbourg, CNRS, IPCMS, UMR 7504, F-67000 Strasbourg, France
| | - L. Garnier
- Université de Strasbourg, CNRS, IPCMS, UMR 7504, F-67000 Strasbourg, France
| | - M. Ormaza
- Université de Strasbourg, CNRS, IPCMS, UMR 7504, F-67000 Strasbourg, France
| | - P. Abufager
- Instituto de Física de Rosario, CONICET and Universidad Nacional de Rosario, Av. Pellegrini 250 (2000) Rosario, Argentina
| | - R. Robles
- Centro de Física de Materiales CFM/MPC (CSIC-UPV/EHU), 20018 Donostia-San Sebastián, Spain
| | - M.-L. Bocquet
- PASTEUR, Département de Chimie, Ecole Normale Supérieure, PSL Research University, Sorbonne Universités, UPMC Univ. Paris 06, CNRS, 75005 Paris, France
| | - M. Ternes
- Institute of Physics II B, RWTH Aachen University, 52074 Aachen, Germany
- Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich, 52425 Jülich, Germany
| | - N. Lorente
- Centro de Física de Materiales CFM/MPC (CSIC-UPV/EHU), 20018 Donostia-San Sebastián, Spain
- Donostia International Physics Center (DIPC), 20018 Donostia-San Sebastián, Spain
| | - L. Limot
- Université de Strasbourg, CNRS, IPCMS, UMR 7504, F-67000 Strasbourg, France
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29
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Yang K, Paul W, Phark SH, Willke P, Bae Y, Choi T, Esat T, Ardavan A, Heinrich AJ, Lutz CP. Coherent spin manipulation of individual atoms on a surface. Science 2019; 366:509-512. [DOI: 10.1126/science.aay6779] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 10/01/2019] [Indexed: 11/03/2022]
Affiliation(s)
- Kai Yang
- IBM Almaden Research Center, San Jose, CA 95120, USA
| | - William Paul
- IBM Almaden Research Center, San Jose, CA 95120, USA
| | - Soo-Hyon Phark
- IBM Almaden Research Center, San Jose, CA 95120, USA
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Republic of Korea
- Department of Physics, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Philip Willke
- IBM Almaden Research Center, San Jose, CA 95120, USA
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Republic of Korea
- Ewha Womans University, Seoul 03760, Republic of Korea
| | - Yujeong Bae
- IBM Almaden Research Center, San Jose, CA 95120, USA
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Republic of Korea
- Ewha Womans University, Seoul 03760, Republic of Korea
| | - Taeyoung Choi
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Republic of Korea
- Department of Physics, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Taner Esat
- IBM Almaden Research Center, San Jose, CA 95120, USA
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Republic of Korea
- Ewha Womans University, Seoul 03760, Republic of Korea
| | - Arzhang Ardavan
- CAESR, Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Andreas J. Heinrich
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Republic of Korea
- Department of Physics, Ewha Womans University, Seoul 03760, Republic of Korea
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30
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Atzori M, Sessoli R. The Second Quantum Revolution: Role and Challenges of Molecular Chemistry. J Am Chem Soc 2019; 141:11339-11352. [PMID: 31287678 DOI: 10.1021/jacs.9b00984] [Citation(s) in RCA: 204] [Impact Index Per Article: 40.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Implementation of modern Quantum Technologies might benefit from the remarkable quantum properties shown by molecular spin systems. In this Perspective, we highlight the role that molecular chemistry can have in the current second quantum revolution, i.e., the use of quantum physics principles to create new quantum technologies, in this specific case by means of molecular components. Herein, we briefly review the current status of the field by identifying the key advances recently made by the molecular chemistry community, such as for example the design of molecular spin qubits with long spin coherence and the realization of multiqubit architectures for quantum gates implementation. With a critical eye to the current state-of-the-art, we also highlight the main challenges needed for the further advancement of the field toward quantum technologies development.
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Affiliation(s)
- Matteo Atzori
- Laboratoire National des Champs Magnétiques Intenses, UPR 3228-CNRS , F-38042 Grenoble , France
| | - Roberta Sessoli
- Dipartimento di Chimica "Ugo Schiff" & INSTM RU , Università degli Studi di Firenze , I-50019 Sesto Fiorentino , Italy
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31
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Yang K, Paul W, Natterer FD, Lado JL, Bae Y, Willke P, Choi T, Ferrón A, Fernández-Rossier J, Heinrich AJ, Lutz CP. Tuning the Exchange Bias on a Single Atom from 1 mT to 10 T. PHYSICAL REVIEW LETTERS 2019; 122:227203. [PMID: 31283288 DOI: 10.1103/physrevlett.122.227203] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Indexed: 06/09/2023]
Abstract
Shrinking spintronic devices to the nanoscale ultimately requires localized control of individual atomic magnetic moments. At these length scales, the exchange interaction plays important roles, such as in the stabilization of spin-quantization axes, the production of spin frustration, and creation of magnetic ordering. Here, we demonstrate the precise control of the exchange bias experienced by a single atom on a surface, covering an energy range of 4 orders of magnitude. The exchange interaction is continuously tunable from milli-eV to micro-eV by adjusting the separation between a spin-1/2 atom on a surface and the magnetic tip of a scanning tunneling microscope. We seamlessly combine inelastic electron tunneling spectroscopy and electron spin resonance to map out the different energy scales. This control of exchange bias over a wide span of energies provides versatile control of spin states, with applications ranging from precise tuning of quantum state properties, to strong exchange bias for local spin doping. In addition, we show that a time-varying exchange interaction generates a localized ac magnetic field that resonantly drives the surface spin. The static and dynamic control of the exchange interaction at the atomic scale provides a new tool to tune the quantum states of coupled-spin systems.
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Affiliation(s)
- Kai Yang
- IBM Almaden Research Center, San Jose, California 95120, USA
| | - William Paul
- IBM Almaden Research Center, San Jose, California 95120, USA
| | - Fabian D Natterer
- IBM Almaden Research Center, San Jose, California 95120, USA
- Physik-Institut, University of Zurich, CH-8057 Zurich, Switzerland
| | - Jose L Lado
- Institute for Theoretical Physics, ETH Zurich, 8093 Zurich, Switzerland
| | - Yujeong Bae
- IBM Almaden Research Center, San Jose, California 95120, USA
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Republic of Korea
- Department of Physics, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Philip Willke
- IBM Almaden Research Center, San Jose, California 95120, USA
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Republic of Korea
- Department of Physics, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Taeyoung Choi
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Republic of Korea
- Department of Physics, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Alejandro Ferrón
- Instituto de Modelado e Innovación Tecnológica (CONICET-UNNE), and Facultad de Ciencias Exactas, Naturales y Agrimensura, Universidad Nacional del Nordeste, Avenida Libertad 5400, W3404AAS Corrientes, Argentina
| | - Joaquín Fernández-Rossier
- QuantaLab, International Iberian Nanotechnology Laboratory (INL), Avenida Mestre José Veiga, 4715-310 Braga, Portugal
- Departamento de Física Aplicada, Universidad de Alicante, San Vicente del Raspeig 03690, Spain
| | - Andreas J Heinrich
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Republic of Korea
- Department of Physics, Ewha Womans University, Seoul 03760, Republic of Korea
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32
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Natterer FD. Waveform-sequencing for scanning tunneling microscopy based pump-probe spectroscopy and pulsed-ESR. MethodsX 2019; 6:1279-1285. [PMID: 31198689 PMCID: PMC6555875 DOI: 10.1016/j.mex.2019.05.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 05/23/2019] [Indexed: 11/24/2022] Open
Abstract
We present here the straightforward implementation of pump-probe methods into existing scanning tunneling microscopy (STM) systems. Our method uses the waveform-sequencing abilities of a standard arbitrary waveform generator (AWG) and a simple mechanical relay switch that either connects the regular STM control electronics or the AWG to the STM system. Our upgrade further enables pulsed-ESR excitation for advanced STM based spin-resonance experiments. We demonstrate the technical implementation, signal detection using a lock-in amplifier, and cross-correlation measurements of DC/DC and DC/RF pulses highlighting our ˜5 ns time resolution, here limited by the speed of the available electronics. Our setup is highly versatile and can be extended to suit other needs of STM based investigations such as required in diverse mapping schemes or the coherent manipulation of qubits. •Plug and Play Pump-Probe Capability•One setup for Pump-Probe Spectroscopy and Pulsed-ESR•Waveform Memory Saving and Versatile due to Waveform-Sequencing of Arbitrary Waveforms.
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33
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Yang K, Willke P, Bae Y, Ferrón A, Lado JL, Ardavan A, Fernández-Rossier J, Heinrich AJ, Lutz CP. Electrically controlled nuclear polarization of individual atoms. NATURE NANOTECHNOLOGY 2018; 13:1120-1125. [PMID: 30397285 DOI: 10.1038/s41565-018-0296-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 10/02/2018] [Indexed: 06/08/2023]
Abstract
Nuclear spins serve as sensitive probes in chemistry1 and materials science2 and are promising candidates for quantum information processing3-6. NMR, the resonant control of nuclear spins, is a powerful tool for probing local magnetic environments in condensed matter systems, which range from magnetic ordering in high-temperature superconductors7,8 and spin liquids9 to quantum magnetism in nanomagnets10,11. Increasing the sensitivity of NMR to the single-atom scale is challenging as it requires a strong polarization of nuclear spins, well in excess of the low polarizations obtained at thermal equilibrium, as well as driving and detecting them individually4,5,12. Strong nuclear spin polarization, known as hyperpolarization, can be achieved through hyperfine coupling with electron spins2. The fundamental mechanism is the conservation of angular momentum: an electron spin flips and a nuclear spin flops. The nuclear hyperpolarization enables applications such as in vivo magnetic resonance imaging using nanoparticles13, and is harnessed for spin-based quantum information processing in quantum dots14 and doped silicon15-17. Here we polarize the nuclear spins of individual copper atoms on a surface using a spin-polarized current in a scanning tunnelling microscope. By employing the electron-nuclear flip-flop hyperfine interaction, the spin angular momentum is transferred from tunnelling electrons to the nucleus of individual Cu atoms. The direction and magnitude of the nuclear polarization is controlled by the direction and amplitude of the current. The nuclear polarization permits the detection of the NMR of individual Cu atoms, which is used to sense the local magnetic environment of the Cu electron spin.
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Affiliation(s)
- Kai Yang
- IBM Almaden Research Center, San Jose, CA, USA
| | - Philip Willke
- IBM Almaden Research Center, San Jose, CA, USA
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul, Republic of Korea
- Department of Physics, Ewha Womans University, Seoul, Republic of Korea
| | - Yujeong Bae
- IBM Almaden Research Center, San Jose, CA, USA
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul, Republic of Korea
- Department of Physics, Ewha Womans University, Seoul, Republic of Korea
| | - Alejandro Ferrón
- Instituto de Modelado e Innovación Tecnológica (CONICET-UNNE) and Facultad de Ciencias Exactas, Naturales y Agrimensura, Universidad Nacional del Nordeste, Corrientes, Argentina
| | - Jose L Lado
- QuantaLab, International Iberian Nanotechnology Laboratory (INL), Braga, Portugal
- Institute for Theoretical Physics, ETH Zurich, Zurich, Switzerland
| | - Arzhang Ardavan
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK
| | - Joaquín Fernández-Rossier
- QuantaLab, International Iberian Nanotechnology Laboratory (INL), Braga, Portugal
- Departamento de Física Aplicada, Universidad de Alicante, San Vicente del Raspeig, Spain
| | - Andreas J Heinrich
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul, Republic of Korea.
- Department of Physics, Ewha Womans University, Seoul, Republic of Korea.
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