1
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Wolf C, Heinrich AJ, Phark SH. On-Surface Atomic Scale Qubit Platform. ACS NANO 2024; 18:28469-28479. [PMID: 39382840 DOI: 10.1021/acsnano.4c07174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2024]
Abstract
Recent advances in scanning probe microscopy combined with electron spin resonance have revealed that localized electron spins on or near surfaces can be utilized as building blocks for the bottom-up assembly of functional quantum-coherent nanostructures. In this perspective, we review the recent advances, lay out advantages of this platform and outline the challenges that lie ahead on the way to the application of on-surface atomic spins to quantum information science and quantum computing.
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Affiliation(s)
- Christoph Wolf
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Korea
- 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
| | - Soo-Hyon Phark
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul 03760, Korea
- Ewha Womans University, Seoul 03760, Korea
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2
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Zheng H, Zi B, Zhou T, Qiu G, Luo Z, Lu Q, Santiago ARP, Zhang Y, Zhao J, Zhang J, He T, Liu Q. Insight into mechanism for remarkable photocatalytic hydrogen evolution of Cu/Pr dual atom co-modified TiO 2. NANOSCALE HORIZONS 2024; 9:1532-1542. [PMID: 38973510 DOI: 10.1039/d4nh00196f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/09/2024]
Abstract
The development of high-activity photocatalysts is crucial for the current large-scale development of photocatalytic hydrogen applications. Herein, we have developed a strategy to significantly enhance the hydrogen photocatalytic activity of Cu/Pr di-atom co-modified TiO2 architectures by selectively anchoring Cu single atoms on the oxygen vacancies of the TiO2 surface and replacing a trace of Ti atoms in the bulk with rare earth Pr atoms. Calculation results demonstrated that the synergistic effect between Cu single atoms and Pr atoms regulates the electronic structure of Cu/Pr-TiO2, thus promoting the separation of photogenerated carriers and their directional migration to Cu single atoms for the photocatalytic reaction. Furthermore, the d-band center of Cu/Pr-TiO2, which is located at -4.70 eV, optimizes the adsorption and desorption behavior of H*. Compared to TiO2, Pr-TiO2, and Cu/TiO2, Cu/Pr-TiO2 displays the best H* adsorption Gibbs free energy (-0.047 eV). Furthermore, experimental results confirmed that the photogenerated carrier lifetime of Cu/Pr-TiO2 is not only the longest (2.45 ns), but its hydrogen production rate (34.90 mmol g-1 h-1) also significantly surpasses those of Cu/TiO2 (13.39 mmol g-1 h-1) and Pr-TiO2 (0.89 mmol g-1 h-1). These findings open up a novel atomic perspective for the development of optimal hydrogen activity in dual-atom-modified TiO2 photocatalysts.
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Affiliation(s)
- Hongshun Zheng
- National Center for International Research on Photoelectric and Energy Materials, Yunnan Key Laboratory for Micro/nano Materials & Technology, School of Materials Science and Engineering, Yunnan University, Kunming 650091, China.
- Southwest United Graduate School, Kunming 650091, China
| | - Baoye Zi
- National Center for International Research on Photoelectric and Energy Materials, Yunnan Key Laboratory for Micro/nano Materials & Technology, School of Materials Science and Engineering, Yunnan University, Kunming 650091, China.
| | - Tong Zhou
- National Center for International Research on Photoelectric and Energy Materials, Yunnan Key Laboratory for Micro/nano Materials & Technology, School of Materials Science and Engineering, Yunnan University, Kunming 650091, China.
| | - Guoyang Qiu
- National Center for International Research on Photoelectric and Energy Materials, Yunnan Key Laboratory for Micro/nano Materials & Technology, School of Materials Science and Engineering, Yunnan University, Kunming 650091, China.
| | - Zhongge Luo
- National Center for International Research on Photoelectric and Energy Materials, Yunnan Key Laboratory for Micro/nano Materials & Technology, School of Materials Science and Engineering, Yunnan University, Kunming 650091, China.
| | - Qingjie Lu
- National Center for International Research on Photoelectric and Energy Materials, Yunnan Key Laboratory for Micro/nano Materials & Technology, School of Materials Science and Engineering, Yunnan University, Kunming 650091, China.
| | - Alain Rafael Puente Santiago
- Walker Department of Mechanical Engineering, University of Texas at Austin, Austin, TX 78712, USA
- Florida International University (FIU), Department of Chemistry and Biochemistry, Miami, FL, USA
| | - Yumin Zhang
- National Center for International Research on Photoelectric and Energy Materials, Yunnan Key Laboratory for Micro/nano Materials & Technology, School of Materials Science and Engineering, Yunnan University, Kunming 650091, China.
| | - Jianhong Zhao
- National Center for International Research on Photoelectric and Energy Materials, Yunnan Key Laboratory for Micro/nano Materials & Technology, School of Materials Science and Engineering, Yunnan University, Kunming 650091, China.
| | - Jin Zhang
- National Center for International Research on Photoelectric and Energy Materials, Yunnan Key Laboratory for Micro/nano Materials & Technology, School of Materials Science and Engineering, Yunnan University, Kunming 650091, China.
| | - Tianwei He
- National Center for International Research on Photoelectric and Energy Materials, Yunnan Key Laboratory for Micro/nano Materials & Technology, School of Materials Science and Engineering, Yunnan University, Kunming 650091, China.
| | - Qingju Liu
- National Center for International Research on Photoelectric and Energy Materials, Yunnan Key Laboratory for Micro/nano Materials & Technology, School of Materials Science and Engineering, Yunnan University, Kunming 650091, China.
- Southwest United Graduate School, Kunming 650091, China
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3
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Reale S, Hwang J, Oh J, Brune H, Heinrich AJ, Donati F, Bae Y. Electrically driven spin resonance of 4f electrons in a single atom on a surface. Nat Commun 2024; 15:5289. [PMID: 38902242 PMCID: PMC11190280 DOI: 10.1038/s41467-024-49447-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 06/05/2024] [Indexed: 06/22/2024] Open
Abstract
A pivotal challenge in quantum technologies lies in reconciling long coherence times with efficient manipulation of the quantum states of a system. Lanthanide atoms, with their well-localized 4f electrons, emerge as a promising solution to this dilemma if provided with a rational design for manipulation and detection. Here we construct tailored spin structures to perform electron spin resonance on a single lanthanide atom using a scanning tunneling microscope. A magnetically coupled structure made of an erbium and a titanium atom enables us to both drive the erbium's 4f electron spins and indirectly probe them through the titanium's 3d electrons. The erbium spin states exhibit an extended spin relaxation time and a higher driving efficiency compared to 3d atoms with spin ½ in similarly coupled structures. Our work provides a new approach to accessing highly protected spin states, enabling their coherent control in an all-electric fashion.
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Affiliation(s)
- Stefano Reale
- Center for Quantum Nanoscience (QNS), Institute for Basic Science (IBS), Seoul, Republic of Korea
- Ewha Womans University, Seoul, Republic of Korea
- Department of Energy, Politecnico di Milano, Milano, Italy
| | - Jiyoon Hwang
- Center for Quantum Nanoscience (QNS), Institute for Basic Science (IBS), Seoul, Republic of Korea
- Department of Physics, Ewha Womans University, Seoul, Republic of Korea
| | - Jeongmin Oh
- Center for Quantum Nanoscience (QNS), Institute for Basic Science (IBS), Seoul, Republic of Korea
- Department of Physics, Ewha Womans University, Seoul, Republic of Korea
| | - Harald Brune
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Andreas J Heinrich
- Center for Quantum Nanoscience (QNS), Institute for Basic Science (IBS), Seoul, Republic of Korea
- Department of Physics, Ewha Womans University, Seoul, Republic of Korea
| | - Fabio Donati
- Center for Quantum Nanoscience (QNS), Institute for Basic Science (IBS), Seoul, Republic of Korea.
- Department of Physics, Ewha Womans University, Seoul, Republic of Korea.
| | - Yujeong Bae
- Center for Quantum Nanoscience (QNS), Institute for Basic Science (IBS), Seoul, Republic of Korea.
- Department of Physics, Ewha Womans University, Seoul, Republic of Korea.
- Empa, Swiss Federal Laboratories for Materials Science and Technology, nanotech@surfaces Laboratory, Dübendorf, Switzerland.
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4
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Wang F, Shen W, Shui Y, Chen J, Wang H, Wang R, Qin Y, Wang X, Wan J, Zhang M, Lu X, Yang T, Song F. Electrically controlled nonvolatile switching of single-atom magnetism in a Dy@C 84 single-molecule transistor. Nat Commun 2024; 15:2450. [PMID: 38503743 PMCID: PMC10951203 DOI: 10.1038/s41467-024-46854-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 03/12/2024] [Indexed: 03/21/2024] Open
Abstract
Single-atom magnetism switching is a key technique towards the ultimate data storage density of computer hard disks and has been conceptually realized by leveraging the spin bistability of a magnetic atom under a scanning tunnelling microscope. However, it has rarely been applied to solid-state transistors, an advancement that would be highly desirable for enabling various applications. Here, we demonstrate realization of the electrically controlled Zeeman effect in Dy@C84 single-molecule transistors, thus revealing a transition in the magnetic moment from 3.8μ B to 5.1μ B for the ground-state GN at an electric field strength of 3 - 10 MV/cm. The consequent magnetoresistance significantly increases from 600% to 1100% at the resonant tunneling point. Density functional theory calculations further corroborate our realization of nonvolatile switching of single-atom magnetism, and the switching stability emanates from an energy barrier of 92 meV for atomic relaxation. These results highlight the potential of using endohedral metallofullerenes for high-temperature, high-stability, high-speed, and compact single-atom magnetic data storage.
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Affiliation(s)
- Feng Wang
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, School of Physics, Nanjing University, Nanjing, 210093, China
- Institute of Atom Manufacturing, Nanjing University, Suzhou, 215163, China
| | - Wangqiang Shen
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
- School of Materials Science and Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Yuan Shui
- MOE Key Laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Jun Chen
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, School of Physics, Nanjing University, Nanjing, 210093, China
- Institute of Atom Manufacturing, Nanjing University, Suzhou, 215163, China
| | - Huaiqiang Wang
- Center for Quantum Transport and Thermal Energy Science, School of Physics and Technology, Nanjing Normal University, Nanjing, 210023, China
| | - Rui Wang
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, School of Physics, Nanjing University, Nanjing, 210093, China
| | - Yuyuan Qin
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, School of Physics, Nanjing University, Nanjing, 210093, China
| | - Xuefeng Wang
- State Key Laboratory of Spintronics Devices and Technologies, School of Electronic Science and Engineering, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, China
| | - Jianguo Wan
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, School of Physics, Nanjing University, Nanjing, 210093, China
| | - Minhao Zhang
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, School of Physics, Nanjing University, Nanjing, 210093, China.
- Institute of Atom Manufacturing, Nanjing University, Suzhou, 215163, China.
| | - Xing Lu
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China.
| | - Tao Yang
- MOE Key Laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an, 710049, China.
| | - Fengqi Song
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, School of Physics, Nanjing University, Nanjing, 210093, China.
- Institute of Atom Manufacturing, Nanjing University, Suzhou, 215163, China.
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5
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Curcella A, Sblendorio D, Rusponi S, Pivetta M, Patthey F, Brune H. Valence Orbitals Driving the Spin Dynamics in a Rare-Earth Single-Atom Magnet. PHYSICAL REVIEW LETTERS 2023; 130:106702. [PMID: 36962040 DOI: 10.1103/physrevlett.130.106702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 01/17/2023] [Accepted: 02/10/2023] [Indexed: 06/18/2023]
Abstract
We combine spin-polarized scanning tunneling microscopy with quantum master equation analysis to investigate the spin dynamics of the single atom magnet Dy on graphene/Ir(111). By performing reading and writing experiments, we show that the strongly spin polarized 5d6s valence shells, as well as their intra-atomic exchange coupling to the 4f shell, determine the pathways for magnetization relaxation and thus the spin dynamics. The good quantum number that determines which states are stable and which mechanisms for reversal exist in a given crystal field is the atomic total angular momentum J_{z}^{tot} and not the commonly considered J_{z}^{4f} of the 4f shell only.
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Affiliation(s)
- A Curcella
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - D Sblendorio
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - S Rusponi
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - M Pivetta
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - F Patthey
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - H Brune
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
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6
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Wang X, Zhu Y, Li H, Lee JM, Tang Y, Fu G. Rare-Earth Single-Atom Catalysts: A New Frontier in Photo/Electrocatalysis. SMALL METHODS 2022; 6:e2200413. [PMID: 35751459 DOI: 10.1002/smtd.202200413] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 05/29/2022] [Indexed: 06/15/2023]
Abstract
Single-atom catalysts (SACs) provide well-defined active sites with 100% atom utilization, and can be prepared using a wide range of support materials. Therefore, they are attracting global attention, especially in the fields of energy conversion and storage. To date, research has focused on transition-metal and precious-metal-based SACs. More recently, rare-earth (RE)-based SACs have emerged as a new frontier in photo/electrocatalysis owing to their unique electronic structure arising from the spin-orbit coupling of the 4f and valence orbitals, unsaturated coordination environment, and unique behavior as charge-transport bridges. However, a systematic review on the role of the RE active sites, catalytic mechanisms, and synthetic methods for RE SACs is lacking. Therefore, in this review, the latest developments in RE SACs having applications in photo/electrocatalysis are summarized and discussed. First, the theoretical advantages of RE SACs for photo/electrocatalysis are briefly introduced, focusing on the roles of the 4f orbitals and coupled energy levels. In addition, the most recent research progress on RE SACs is summarized for several important photo/electrocatalytic reactions and the corresponding catalytic mechanisms are discussed. Further, the synthetic strategies for the production of RE SACs are reported. Finally, challenges for the development of RE SACs are highlighted, along with future research directions and perspectives.
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Affiliation(s)
- Xuan Wang
- Jiangsu Key Laboratory of New Power Batteries, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing, 210023, P. R. China
| | - Yu Zhu
- Jiangsu Key Laboratory of New Power Batteries, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing, 210023, P. R. China
| | - Hao Li
- Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai, 980-8577, Japan
| | - Jong-Min Lee
- School of Chemical and Biomedical Engineering, Nanyang Technology University, Singapore, 637459, Singapore
| | - Yawen Tang
- Jiangsu Key Laboratory of New Power Batteries, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing, 210023, P. R. China
| | - Gengtao Fu
- Jiangsu Key Laboratory of New Power Batteries, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing, 210023, P. R. China
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7
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Bellini V, Rusponi S, Kolorenč J, Mahatha SK, Valbuena MA, Persichetti L, Pivetta M, Sorokin BV, Merk D, Reynaud S, Sblendorio D, Stepanow S, Nistor C, Gargiani P, Betto D, Mugarza A, Gambardella P, Brune H, Carbone C, Barla A. Slow Magnetic Relaxation of Dy Adatoms with In-Plane Magnetic Anisotropy on a Two-Dimensional Electron Gas. ACS NANO 2022; 16:11182-11193. [PMID: 35770912 PMCID: PMC9330770 DOI: 10.1021/acsnano.2c04048] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We report on the magnetic properties of Dy atoms adsorbed on the (001) surface of SrTiO3. X-ray magnetic circular dichroism reveals slow relaxation of the Dy magnetization on a time scale of about 800 s at 2.5 K, unusually associated with an easy-plane magnetic anisotropy. We attribute these properties to Dy atoms occupying hollow adsorption sites on the TiO2-terminated surface. Conversely, Ho atoms adsorbed on the same surface show paramagnetic behavior down to 2.5 K. With the help of atomic multiplet simulations and first-principles calculations, we establish that Dy populates also the top-O and bridge sites on the coexisting SrO-terminated surface. A simple magnetization relaxation model predicts these two sites to have an even longer magnetization lifetime than the hollow site. Moreover, the adsorption of Dy on the insulating SrTiO3 crystal leads, regardless of the surface termination, to the formation of a spin-polarized two-dimensional electron gas of Ti 3dxy character, together with an antiferromagnetic Dy-Ti coupling. Our findings support the feasibility of tuning the magnetic properties of the rare-earth atoms by acting on the substrate electronic gas with electric fields.
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Affiliation(s)
- Valerio Bellini
- S3-Istituto
di Nanoscienze-CNR, Via
Campi 213/A, I-41125 Modena, Italy
| | - Stefano Rusponi
- Institute
of Physics, Ecole Polytechnique Fédérale de Lausanne
(EPFL), Station 3, CH-1015 Lausanne, Switzerland
| | - Jindřich Kolorenč
- Institute
of Physics (FZU), Czech Academy of Sciences, Na Slovance 2, CZ-182
21 Prague, Czech Republic
| | - Sanjoy K. Mahatha
- Istituto
di Struttura della Materia (ISM), Consiglio Nazionale delle Ricerche
(CNR), I-34149 Trieste, Italy
- School
of
Physics and Materials Science, Thapar Institute
of Engineering and Technology, Patiala 147004, India
| | - Miguel Angel Valbuena
- Catalan
Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST,
Campus UAB, Bellaterra, E-08193 Barcelona, Spain
- Instituto
Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nanoscience), E-28049 Madrid, Spain
| | - Luca Persichetti
- Department
of Materials, ETH Zurich, CH-8093 Zurich, Switzerland
- Dipartimento
di Fisica, Università di Roma “Tor
Vergata”, I-00133 Roma, Italy
| | - Marina Pivetta
- Institute
of Physics, Ecole Polytechnique Fédérale de Lausanne
(EPFL), Station 3, CH-1015 Lausanne, Switzerland
| | - Boris V. Sorokin
- Institute
of Physics, Ecole Polytechnique Fédérale de Lausanne
(EPFL), Station 3, CH-1015 Lausanne, Switzerland
| | - Darius Merk
- Institute
of Physics, Ecole Polytechnique Fédérale de Lausanne
(EPFL), Station 3, CH-1015 Lausanne, Switzerland
| | - Sébastien Reynaud
- Institute
of Physics, Ecole Polytechnique Fédérale de Lausanne
(EPFL), Station 3, CH-1015 Lausanne, Switzerland
| | - Dante Sblendorio
- Institute
of Physics, Ecole Polytechnique Fédérale de Lausanne
(EPFL), Station 3, CH-1015 Lausanne, Switzerland
| | | | - Corneliu Nistor
- Department
of Materials, ETH Zurich, CH-8093 Zurich, Switzerland
| | | | - Davide Betto
- European
Synchrotron Radiation Facility, F-38043 Grenoble Cedex, France
| | - Aitor Mugarza
- Catalan
Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST,
Campus UAB, Bellaterra, E-08193 Barcelona, Spain
- Institució
Catalana de Recerca i Estudis Avançats (ICREA), Barcelona E-08010, Spain
| | | | - Harald Brune
- Institute
of Physics, Ecole Polytechnique Fédérale de Lausanne
(EPFL), Station 3, CH-1015 Lausanne, Switzerland
| | - Carlo Carbone
- Istituto
di Struttura della Materia (ISM), Consiglio Nazionale delle Ricerche
(CNR), I-34149 Trieste, Italy
| | - Alessandro Barla
- Istituto
di Struttura della Materia (ISM), Consiglio Nazionale delle Ricerche
(CNR), I-34149 Trieste, Italy
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8
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Koutsouflakis E, Krylov D, Bachellier N, Sostina D, Dubrovin V, Liu F, Spree L, Velkos G, Schimmel S, Wang Y, Büchner B, Westerström R, Bulbucan C, Kirkpatrick K, Muntwiler M, Dreiser J, Greber T, Avdoshenko SM, Dorn H, Popov AA. Metamagnetic transition and a loss of magnetic hysteresis caused by electron trapping in monolayers of single-molecule magnet Tb 2@C 79N. NANOSCALE 2022; 14:9877-9892. [PMID: 35781298 DOI: 10.1039/d1nr08475e] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Realization of stable spin states in surface-supported magnetic molecules is crucial for their applications in molecular spintronics, memory storage or quantum information processing. In this work, we studied the surface magnetism of dimetallo-azafullerene Tb2@C79N, showing a broad magnetic hysteresis in a bulk form. Surprisingly, monolayers of Tb2@C79N exhibited a completely different behavior, with the prevalence of a ground state with antiferromagnetic coupling at low magnetic field and a metamagnetic transition in the magnetic field of 2.5-4 T. Monolayers of Tb2@C79N were deposited onto Cu(111) and Au(111) by evaporation in ultra-high vacuum conditions, and their topography and electronic structure were characterized by scanning tunneling microscopy and spectroscopy (STM/STS). X-ray photoelectron spectroscopy (XPS), in combination with DFT studies, revealed that the nitrogen atom of the azafullerene cage tends to avoid metallic surfaces. Magnetic properties of the (sub)monolayers were then studied by X-ray magnetic circular dichroism (XMCD) at the Tb-M4,5 absorption edge. While in bulk powder samples Tb2@C79N behaves as a single-molecule magnet with ferromagnetically coupled magnetic moments and blocking of magnetization at 28 K, its monolayers exhibited a different ground state with antiferromagnetic coupling of Tb magnetic moments. To understand if this unexpected behavior is caused by a strong hybridization of fullerenes with metallic substrates, XMCD measurements were also performed for Tb2@C79N adsorbed on h-BN|Rh(111) and MgO|Ag(100). The co-existence of two forms of Tb2@C79N was found on these substrates as well, but magnetization curves showed narrow magnetic hysteresis detectable up to 25 K. The non-magnetic state of Tb2@C79N in monolayers is assigned to anionic Tb2@C79N- species with doubly-occupied Tb-Tb bonding orbital and antiferromagnetic coupling of the Tb moments. A charge transfer from the substrate or trapping of secondary electrons are discussed as a plausible origin of these species.
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Affiliation(s)
- Emmanouil Koutsouflakis
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, 01069 Dresden, Germany.
| | - Denis Krylov
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, 01069 Dresden, Germany.
| | - Nicolas Bachellier
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Daria Sostina
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Vasilii Dubrovin
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, 01069 Dresden, Germany.
| | - Fupin Liu
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, 01069 Dresden, Germany.
| | - Lukas Spree
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, 01069 Dresden, Germany.
| | - Georgios Velkos
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, 01069 Dresden, Germany.
| | - Sebastian Schimmel
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, 01069 Dresden, Germany.
| | - Yaofeng Wang
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, 01069 Dresden, Germany.
| | - Bernd Büchner
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, 01069 Dresden, Germany.
| | - Rasmus Westerström
- The Division of Synchrotron Radiation Research, Lund University, SE-22100 Lund, Sweden
- NanoLund, Lund University, Box 118, 22100 Lund, Sweden
| | - Claudiu Bulbucan
- The Division of Synchrotron Radiation Research, Lund University, SE-22100 Lund, Sweden
- NanoLund, Lund University, Box 118, 22100 Lund, Sweden
| | - Kyle Kirkpatrick
- Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA
| | - Matthias Muntwiler
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Jan Dreiser
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Thomas Greber
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
- Physik-Institut der Universität Zürich, Winterthurerstr. 190, CH-8057 Zürich, Switzerland
| | - Stas M Avdoshenko
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, 01069 Dresden, Germany.
| | - Harry Dorn
- Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA
| | - Alexey A Popov
- Leibniz Institute for Solid State and Materials Research (IFW Dresden), Helmholtzstraße 20, 01069 Dresden, Germany.
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Navrátil J, Otyepka M, Błoński P. OsPd bimetallic dimer pushes the limit of magnetic anisotropy in atom-sized magnets for data storage. NANOTECHNOLOGY 2022; 33:215001. [PMID: 35147526 DOI: 10.1088/1361-6528/ac5447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 02/10/2022] [Indexed: 06/14/2023]
Abstract
The growing gap between the volume of digital data being created and the extent of available storage capacities stimulates intensive research into surface-supported, well-ordered array of atom-sized magnets that represents the ultimate limit of magnetic data storage. Anchoring transition-metal heterodimers in vacancy defects in the graphene lattice has been identified as a vivid strategy to achieve large magnetic anisotropy energy (MAE) up to 80 meV with an easy axis aligned along the dimer bond. In this paper we have made a significant leap forward finding out MAE of 119 meV for an OsPt dimer and 170 meV for an OsPd dimer bound to a single nitrogen-decorated vacancy defect. The system with the highest MAE and with the theoretical storage density of ∼490 Tb·inch-2pushes the current limit of theoretical blocking temperature in graphene-supported transition-metal dimers from ∼20 to ∼44 K assuming the relaxation time of 10 years. The mechanism of the enhanced MAE is discussed.
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Affiliation(s)
- Jan Navrátil
- Department of Physical Chemistry, Faculty of Science, Palacký University Olomouc, tř. 17 listopadu 12, 779 00 Olomouc, Czech Republic
- Regional Centre of Advanced Technologies and Materials, Czech Advanced Technology and Research Institute (CATRIN), Palacký University Olomouc, Šlechtitelů 27, 779 00 Olomouc, Czech Republic
| | - Michal Otyepka
- Regional Centre of Advanced Technologies and Materials, Czech Advanced Technology and Research Institute (CATRIN), Palacký University Olomouc, Šlechtitelů 27, 779 00 Olomouc, Czech Republic
| | - Piotr Błoński
- Regional Centre of Advanced Technologies and Materials, Czech Advanced Technology and Research Institute (CATRIN), Palacký University Olomouc, Šlechtitelů 27, 779 00 Olomouc, Czech Republic
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