1
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Aguirre A, Pinar Solé A, Soler Polo D, González-Orellana C, Thakur A, Ortuzar J, Stesovych O, Kumar M, Peña-Díaz M, Weber A, Tallarida M, Dai J, Dreiser J, Muntwiler M, Rogero C, Pascual JI, Jelínek P, Ilyn M, Corso M. Ferromagnetic Order in 2D Layers of Transition Metal Dichlorides. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2402723. [PMID: 38665115 DOI: 10.1002/adma.202402723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 04/08/2024] [Indexed: 05/07/2024]
Abstract
Magnetism in two dimensions is traditionally considered an exotic phase mediated by spin fluctuations, but far from collinearly ordered in the ground state. Recently, 2D magnetic states have been discovered in layered van der Waals compounds. Their robust and tunable magnetic state by material composition, combined with reduced dimensionality, foresee a strong potential as a key element in magnetic devices. Here, a class of 2D magnets based on metallic chlorides is presented. The magnetic order survives on top of a metallic substrate, even down to the monolayer limit, and can be switched from perpendicular to in-plane by substituting the metal ion from iron to nickel. Using functionalized STM tips as magnetic sensors, local exchange fields are identified, even in the absence of an external magnetic field. Since the compounds are processable by molecular beam epitaxy techniques, they provide a platform with large potential for incorporation into current device technologies.
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Affiliation(s)
- Andrea Aguirre
- Centro de Física de Materiales CSIC-UPV/EHU, Donostia-San Sebastián, 20018, Spain
- CIC nanoGUNE-BRTA, Donostia-San Sebastián, 20018, Spain
| | - Andrés Pinar Solé
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, Prague, 16200, Czech Republic
| | - Diego Soler Polo
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, Prague, 16200, Czech Republic
| | | | - Amitayush Thakur
- Centro de Física de Materiales CSIC-UPV/EHU, Donostia-San Sebastián, 20018, Spain
| | - Jon Ortuzar
- CIC nanoGUNE-BRTA, Donostia-San Sebastián, 20018, Spain
| | - Oleksandr Stesovych
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, Prague, 16200, Czech Republic
| | - Manish Kumar
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, Prague, 16200, Czech Republic
| | - Marina Peña-Díaz
- Centro de Física de Materiales CSIC-UPV/EHU, Donostia-San Sebastián, 20018, Spain
| | - Andrew Weber
- Centro de Física de Materiales CSIC-UPV/EHU, Donostia-San Sebastián, 20018, Spain
| | | | - Ji Dai
- ALBA, Cerdanyola del Vallès, Barcelona, 08290, Spain
| | - Jan Dreiser
- Paul Scherrer Institut, Forschungsstrasse 111, Villigen, CH-5232, Switzerland
| | - Matthias Muntwiler
- Paul Scherrer Institut, Forschungsstrasse 111, Villigen, CH-5232, Switzerland
| | - Celia Rogero
- Centro de Física de Materiales CSIC-UPV/EHU, Donostia-San Sebastián, 20018, Spain
- Donostia International Physics Center, Donostia-San Sebastián, 20018, Spain
| | - José Ignacio Pascual
- CIC nanoGUNE-BRTA, Donostia-San Sebastián, 20018, Spain
- Ikerbasque, Basque Foundation for Science, Bilbao, 48013, Spain
| | - Pavel Jelínek
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, Prague, 16200, Czech Republic
| | - Maxim Ilyn
- Centro de Física de Materiales CSIC-UPV/EHU, Donostia-San Sebastián, 20018, Spain
| | - Martina Corso
- Centro de Física de Materiales CSIC-UPV/EHU, Donostia-San Sebastián, 20018, Spain
- Donostia International Physics Center, Donostia-San Sebastián, 20018, Spain
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2
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Lee H, Im H, Choi BK, Park K, Chen Y, Ruan W, Zhong Y, Lee JE, Ryu H, Crommie MF, Shen ZX, Hwang C, Mo SK, Hwang J. Controlling structure and interfacial interaction of monolayer TaSe 2 on bilayer graphene. NANO CONVERGENCE 2024; 11:14. [PMID: 38622355 PMCID: PMC11018566 DOI: 10.1186/s40580-024-00422-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Accepted: 04/01/2024] [Indexed: 04/17/2024]
Abstract
Tunability of interfacial effects between two-dimensional (2D) crystals is crucial not only for understanding the intrinsic properties of each system, but also for designing electronic devices based on ultra-thin heterostructures. A prerequisite of such heterostructure engineering is the availability of 2D crystals with different degrees of interfacial interactions. In this work, we report a controlled epitaxial growth of monolayer TaSe2 with different structural phases, 1H and 1 T, on a bilayer graphene (BLG) substrate using molecular beam epitaxy, and its impact on the electronic properties of the heterostructures using angle-resolved photoemission spectroscopy. 1H-TaSe2 exhibits significant charge transfer and band hybridization at the interface, whereas 1 T-TaSe2 shows weak interactions with the substrate. The distinct interfacial interactions are attributed to the dual effects from the differences of the work functions as well as the relative interlayer distance between TaSe2 films and BLG substrate. The method demonstrated here provides a viable route towards interface engineering in a variety of transition-metal dichalcogenides that can be applied to future nano-devices with designed electronic properties.
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Affiliation(s)
- Hyobeom Lee
- Department of Physics and Institute of Quantum Convergence Technology, Kangwon National University, Chuncheon, South Korea
| | - Hayoon Im
- Department of Physics, Pusan National University, Busan, South Korea
| | - Byoung Ki Choi
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Kyoungree Park
- Department of Physics and Institute of Quantum Convergence Technology, Kangwon National University, Chuncheon, South Korea
| | - Yi Chen
- Department of Physics, University of California, Berkeley, CA, USA
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, China
- Collaborative Innovation Center of Quantum Matter, Beijing, 100871, China
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, Beijing, 100871, China
| | - Wei Ruan
- Department of Physics, University of California, Berkeley, CA, USA
- State Key Laboratory of Surface Physics, New Cornerstone Science Laboratory, and Department of Physics, Fudan University, Shanghai, China
| | - Yong Zhong
- Geballe Laboratory for Advanced Materials, Department of Physics and Applied Physics, Stanford University, Stanford, CA, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Ji-Eun Lee
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Max Planck POSTECH Center for Complex Phase Materials, Pohang University of Science and Technology, Pohang, South Korea
| | - Hyejin Ryu
- Center for Spintronics, Korea Institute of Science and Technology, Seoul, South Korea
| | - Michael F Crommie
- Department of Physics, University of California, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Zhi-Xun Shen
- Geballe Laboratory for Advanced Materials, Department of Physics and Applied Physics, Stanford University, Stanford, CA, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Choongyu Hwang
- Department of Physics, Pusan National University, Busan, South Korea.
| | - Sung-Kwan Mo
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - Jinwoong Hwang
- Department of Physics and Institute of Quantum Convergence Technology, Kangwon National University, Chuncheon, South Korea.
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3
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Hwang J, Ruan W, Chen Y, Tang S, Crommie MF, Shen ZX, Mo SK. Charge density waves in two-dimensional transition metal dichalcogenides. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2024; 87:044502. [PMID: 38518359 DOI: 10.1088/1361-6633/ad36d3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 03/22/2024] [Indexed: 03/24/2024]
Abstract
Charge density wave (CDW is one of the most ubiquitous electronic orders in quantum materials. While the essential ingredients of CDW order have been extensively studied, a comprehensive microscopic understanding is yet to be reached. Recent research efforts on the CDW phenomena in two-dimensional (2D) materials provide a new pathway toward a deeper understanding of its complexity. This review provides an overview of the CDW orders in 2D with atomically thin transition metal dichalcogenides (TMDCs) as the materials platform. We mainly focus on the electronic structure investigations on the epitaxially grown TMDC samples with angle-resolved photoemission spectroscopy and scanning tunneling microscopy/spectroscopy as complementary experimental tools. We discuss the possible origins of the 2D CDW, novel quantum states coexisting with them, and exotic types of charge orders that can only be realized in the 2D limit.
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Affiliation(s)
- Jinwoong Hwang
- Department of Physics and Institute of Quantum Convergence Technology, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Wei Ruan
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200438, People's Republic of China
| | - Yi Chen
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China
- Collaborative Innovation Center of Quantum Matter, Beijing 100871, People's Republic of China
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, Beijing 100871, People's Republic of China
| | - Shujie Tang
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, People's Republic of China
| | - Michael F Crommie
- Department of Physics, University of California, Berkeley, CA, United States of America
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States of America
- Kavli Energy NanoSciences Institute at the University of California at Berkeley, Berkeley, CA 94720, United States of America
| | - Zhi-Xun Shen
- Geballe Laboratory for Advanced Materials, Departments of Physics and Applied Physics, Stanford University, Stanford, CA, United States of America
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, United States of America
| | - Sung-Kwan Mo
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 United States of America
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Wan W, Harsh R, Meninno A, Dreher P, Sajan S, Guo H, Errea I, de Juan F, Ugeda MM. Evidence for ground state coherence in a two-dimensional Kondo lattice. Nat Commun 2023; 14:7005. [PMID: 37919299 PMCID: PMC10622499 DOI: 10.1038/s41467-023-42803-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 10/16/2023] [Indexed: 11/04/2023] Open
Abstract
Kondo lattices are ideal testbeds for the exploration of heavy-fermion quantum phases of matter. While our understanding of Kondo lattices has traditionally relied on complex bulk f-electron systems, transition metal dichalcogenide heterobilayers have recently emerged as simple, accessible and tunable 2D Kondo lattice platforms where, however, their ground state remains to be established. Here we present evidence of a coherent ground state in the 1T/1H-TaSe2 heterobilayer by means of scanning tunneling microscopy/spectroscopy at 340 mK. Our measurements reveal the existence of two symmetric electronic resonances around the Fermi energy, a hallmark of coherence in the spin lattice. Spectroscopic imaging locates both resonances at the central Ta atom of the charge density wave of the 1T phase, where the localized magnetic moment is held. Furthermore, the evolution of the electronic structure with the magnetic field reveals a non-linear increase of the energy separation between the electronic resonances. Aided by ab initio and auxiliary-fermion mean-field calculations, we demonstrate that this behavior is inconsistent with a fully screened Kondo lattice, and suggests a ground state with magnetic order mediated by conduction electrons. The manifestation of magnetic coherence in TMD-based 2D Kondo lattices enables the exploration of magnetic quantum criticality, Kondo breakdown transitions and unconventional superconductivity in the strict two-dimensional limit.
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Affiliation(s)
- Wen Wan
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal 4, 20018, San Sebastián, Spain
- Materials Genome Institute, Shanghai University, 200444, Shanghai, China
| | - Rishav Harsh
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal 4, 20018, San Sebastián, Spain
| | - Antonella Meninno
- Centro de Física de Materiales (CSIC-UPV/EHU), Paseo Manuel de Lardizábal 5, 20018, San Sebastián, Spain
- Departamento de Física Aplicada, Escuela de Ingeniería de Gipuzkoa, University of the Basque Country (UPV/EHU), Plaza Europa 1, 20018, San Sebastián, Spain
| | - Paul Dreher
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal 4, 20018, San Sebastián, Spain
| | - Sandra Sajan
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal 4, 20018, San Sebastián, Spain
| | - Haojie Guo
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal 4, 20018, San Sebastián, Spain
| | - Ion Errea
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal 4, 20018, San Sebastián, Spain
- Centro de Física de Materiales (CSIC-UPV/EHU), Paseo Manuel de Lardizábal 5, 20018, San Sebastián, Spain
- Departamento de Física Aplicada, Escuela de Ingeniería de Gipuzkoa, University of the Basque Country (UPV/EHU), Plaza Europa 1, 20018, San Sebastián, Spain
| | - Fernando de Juan
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal 4, 20018, San Sebastián, Spain.
- Ikerbasque, Basque Foundation for Science, 48013, Bilbao, Spain.
| | - Miguel M Ugeda
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal 4, 20018, San Sebastián, Spain.
- Centro de Física de Materiales (CSIC-UPV/EHU), Paseo Manuel de Lardizábal 5, 20018, San Sebastián, Spain.
- Ikerbasque, Basque Foundation for Science, 48013, Bilbao, Spain.
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5
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Koussir H, Chernukha Y, Sthioul C, Haber E, Peric N, Biadala L, Capiod P, Berthe M, Lefebvre I, Wallart X, Grandidier B, Diener P. Large-Area Epitaxial Mott Insulating 1T-TaSe 2 Monolayer on GaP(111)B. NANO LETTERS 2023; 23:9413-9419. [PMID: 37820373 DOI: 10.1021/acs.nanolett.3c02813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/13/2023]
Abstract
Two-dimensional Mott materials have recently been reported in the dichalcogenide family with high potential for Mottronic applications. Nevertheless, their widespread use as a single or few layers is hampered by their limited device integration resulting from their growth on graphene, a metallic substrate. Here, we report on the fabrication of 1T-TaSe2 monolayers grown by molecular beam epitaxy on semiconducting gallium phosphide substrates. At the nanoscale, the charge density wave reconstruction and a moiré pattern resulting from the monolayer interaction with the substrate are observed by scanning tunneling microscopy. The fully open gap unveiled by tunneling spectroscopy, which can be further manipulated by the proximity of a metal tip, is confirmed by transport measurements from micrometric to millimetric scales, demonstrating a robust Mott insulating phase at up to 400 K.
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Affiliation(s)
- H Koussir
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - Y Chernukha
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - C Sthioul
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - E Haber
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - N Peric
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - L Biadala
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - P Capiod
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - M Berthe
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - I Lefebvre
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - X Wallart
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - B Grandidier
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - P Diener
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
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6
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Kim D, Pandey J, Jeong J, Cho W, Lee S, Cho S, Yang H. Phase Engineering of 2D Materials. Chem Rev 2023; 123:11230-11268. [PMID: 37589590 DOI: 10.1021/acs.chemrev.3c00132] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/18/2023]
Abstract
Polymorphic 2D materials allow structural and electronic phase engineering, which can be used to realize energy-efficient, cost-effective, and scalable device applications. The phase engineering covers not only conventional structural and metal-insulator transitions but also magnetic states, strongly correlated band structures, and topological phases in rich 2D materials. The methods used for the local phase engineering of 2D materials include various optical, geometrical, and chemical processes as well as traditional thermodynamic approaches. In this Review, we survey the precise manipulation of local phases and phase patterning of 2D materials, particularly with ideal and versatile phase interfaces for electronic and energy device applications. Polymorphic 2D materials and diverse quantum materials with their layered, vertical, and lateral geometries are discussed with an emphasis on the role and use of their phase interfaces. Various phase interfaces have demonstrated superior and unique performance in electronic and energy devices. The phase patterning leads to novel homo- and heterojunction structures of 2D materials with low-dimensional phase boundaries, which highlights their potential for technological breakthroughs in future electronic, quantum, and energy devices. Accordingly, we encourage researchers to investigate and exploit phase patterning in emerging 2D materials.
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Affiliation(s)
- Dohyun Kim
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Juhi Pandey
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Juyeong Jeong
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Woohyun Cho
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Seungyeon Lee
- Division of Chemical Engineering and Materials Science, Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul 03760, Korea
| | - Suyeon Cho
- Division of Chemical Engineering and Materials Science, Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul 03760, Korea
| | - Heejun Yang
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
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7
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Sierda E, Huang X, Badrtdinov DI, Kiraly B, Knol EJ, Groenenboom GC, Katsnelson MI, Rösner M, Wegner D, Khajetoorians AA. Quantum simulator to emulate lower-dimensional molecular structure. Science 2023; 380:1048-1052. [PMID: 37289865 DOI: 10.1126/science.adf2685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 05/10/2023] [Indexed: 06/10/2023]
Abstract
Bottom-up quantum simulators have been developed to quantify the role of various interactions, dimensionality, and structure in creating electronic states of matter. Here, we demonstrated a solid-state quantum simulator emulating molecular orbitals, based solely on positioning individual cesium atoms on an indium antimonide surface. Using scanning tunneling microscopy and spectroscopy, combined with ab initio calculations, we showed that artificial atoms could be made from localized states created from patterned cesium rings. These artificial atoms served as building blocks to realize artificial molecular structures with different orbital symmetries. These corresponding molecular orbitals allowed us to simulate two-dimensional structures reminiscent of well-known organic molecules. This platform could further be used to monitor the interplay between atomic structures and the resulting molecular orbital landscape with submolecular precision.
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Affiliation(s)
- E Sierda
- Institute for Molecules and Materials, Radboud University, Nijmegen, Netherlands
| | - X Huang
- Institute for Molecules and Materials, Radboud University, Nijmegen, Netherlands
| | - D I Badrtdinov
- Institute for Molecules and Materials, Radboud University, Nijmegen, Netherlands
| | - B Kiraly
- Institute for Molecules and Materials, Radboud University, Nijmegen, Netherlands
| | - E J Knol
- Institute for Molecules and Materials, Radboud University, Nijmegen, Netherlands
| | - G C Groenenboom
- Institute for Molecules and Materials, Radboud University, Nijmegen, Netherlands
| | - M I Katsnelson
- Institute for Molecules and Materials, Radboud University, Nijmegen, Netherlands
| | - M Rösner
- Institute for Molecules and Materials, Radboud University, Nijmegen, Netherlands
| | - D Wegner
- Institute for Molecules and Materials, Radboud University, Nijmegen, Netherlands
| | - A A Khajetoorians
- Institute for Molecules and Materials, Radboud University, Nijmegen, Netherlands
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8
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Weng X, David P, Guisset V, Martinelli L, Geaymond O, Coraux J, Renaud G. Superstructures, Commensurations, and Rotation of Single-Layer TaS 2 on Au(111) Induced by Cs Intercalation/Deintercalation. ACS NANO 2023; 17:5459-5471. [PMID: 36912862 DOI: 10.1021/acsnano.2c10655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
We use in situ synchrotron grazing incidence X-ray diffraction and X-ray reflectivity to investigate with high resolution the structure of a two-dimensional single layer of tantalum sulfide grown on a Au(111) surface and its evolution during intercalation by Cs atoms and deintercalation, which decouples and recouples the two materials, respectively. The grown single layer consists of a mixture of TaS2 and its S-depleted version, TaS, both aligned with gold, and forming moirés where 7 (respectively 13) lattice constants of the 2D layer almost perfectly match 8 (respectively 15) substrate lattice constants. Intercalation fully decouples the system by lifting the single layer by ∼370 pm and induces an increase of its lattice parameter by 1-2 picometers. The system gradually evolves, during cycles of intercalation/deintercalation assisted by an H2S atmosphere, toward a final coupled state consisting of the fully stoichiometric TaS2 dichalcogenide whose moiré is found very close to the 7/8 commensurability. The reactive H2S atmosphere appears necessary to achieve full deintercalation, presumably by preventing S depletion and the concomitant strong bonding with the intercalant. The structural quality of the layer improves during the cyclic treatment. In parallel, because they are decoupled from the substrate by the intercalation of cesium, some of the TaS2 flakes rotate by 30°. These produce two additional superlattices with characteristic diffraction patterns of different origins. The first is aligned with gold's high symmetry crystallographic directions and is a commensurate moiré ((6 × 6)-Au(111) coinciding with (3√3 × 3√3)R30°-TaS2). The second is incommensurate and corresponds to a near coincidence of (6 × 6) unit cells of 30°-rotated TaS2 with (4√3 × 4√3)Au(111) surface ones. This structure, which is less coupled to gold, might be related to the ∼(3× 3) charge density wave previously reported even at room temperature in TaS2 grown on noninteracting substrates. A (3 × 3) superstructure of 30°-rotated TaS2 islands is indeed revealed by complementary scanning tunneling microscopy.
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Affiliation(s)
- Xiaorong Weng
- Université Grenoble Alpes, CEA, IRIG/MEM/NRS, 38000 Grenoble, France
| | - Philippe David
- Université Grenoble Alpes, CNRS, Institut NEEL, 38000 Grenoble, France
| | - Valérie Guisset
- Université Grenoble Alpes, CNRS, Institut NEEL, 38000 Grenoble, France
| | - Lucio Martinelli
- Université Grenoble Alpes, CNRS, Institut NEEL, 38000 Grenoble, France
| | - Olivier Geaymond
- Université Grenoble Alpes, CNRS, Institut NEEL, 38000 Grenoble, France
| | - Johann Coraux
- Université Grenoble Alpes, CNRS, Institut NEEL, 38000 Grenoble, France
| | - Gilles Renaud
- Université Grenoble Alpes, CEA, IRIG/MEM/NRS, 38000 Grenoble, France
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9
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Tunability of the Superconductivity of NbSe 2 Films Grown by Two-Step Vapor Deposition. Molecules 2023; 28:molecules28031059. [PMID: 36770735 PMCID: PMC9921890 DOI: 10.3390/molecules28031059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 01/19/2023] [Accepted: 01/19/2023] [Indexed: 01/24/2023] Open
Abstract
Layered metallic transition-metal dichalcogenides (TMDCs) are ideal platforms for exploring their fascinating electronic properties at two-dimensional limits, such as their charge density wave (CDW) and superconductivity. Therefore, developing ways to improve the crystallization quality of TMDCs is urgently needed. Here we report superconductively tunable NbSe2 grown by a two-step vapor deposition method. By optimizing the sputtering conditions, superconducting NbSe2 films were prepared from highly crystalline Nb films. The bilayer NbSe2 films showed a superconducting transition temperature that was up to 3.1 K. Similar to the salt-assisted chemical vapor deposition (CVD) method, superconducting monolayer NbSe2 crystals were also grown from a selenide precursor, and the growth strategy is suitable for many other TMDCs. Our growth method not only provides a way to improve the crystalline quality of TMDC films, but also gives new insight into the growth of monolayer TMDCs. It holds promise for exploring two-dimensional TMDCs in fundamental research and device applications.
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10
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Liu Y, Feng Y, Hu L, Wu X, Qiao S, Gao G. Structural, electronic phase transitions and thermal spin transport properties in 2D NbSe 2 and NbS 2: a first-principles study. Phys Chem Chem Phys 2023; 25:1632-1641. [PMID: 36305285 DOI: 10.1039/d2cp03417d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
How to effectively tune 2D electronic and magnetic properties is key to developing novel spintronic materials and devices. Although the strain induced metal-to-half-metal electronic phase transition (EPT) has been studied in 2H NbSe2 and NbS2 monolayers, the 1T phase, the Coulomb interaction and the transport properties have not been explored. Here, using first-principles calculations in junction with nonequilibrium Green's function, we present a comprehensive and comparative study on the strain tuned structural, electronic, magnetic and thermal spin transport properties for NbSe2 and NbS2 monolayers with and without Coulomb interaction. It is found that the Coulomb interaction makes the strain induced 2H-to-1T structural phase transition easier. Similar to the 2H phase, there is also a strain induced metal-to-half-metal EPT for the 1T phase without Coulomb interaction, and the Coulomb interaction makes the ETP easier. Remarkably, the 2H-NbSe2 monolayer with Coulomb interaction is a bipolar spin gapless semiconductor (SGS), and novel Dirac half-metal and usually SGS can be obtained by the tensile strain. In addition, we predict the excellent spin Seebeck effect and thermal spin diode effect in the bipolar SGS of the 2H-NbSe2 monolayer with Coulomb interaction, and expect the spin filtering effect and high magnetoresistance in the half-metals driven by the strain. We also discuss the strength of Coulomb interaction by comparing the theoretical and available experimental electronic states, indicating the indispensability of Coulomb interactions. These results suggest that 2D NbSe2 and NbS2 are promising candidates for phase-change spintronic materials and devices, and will stimulate extensive studies on this class of 2D systems.
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Affiliation(s)
- Yuqi Liu
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China.
| | - Yulin Feng
- College of Physics and Electronic Science, Hubei Normal University, Huangshi 435002, China
| | - Lei Hu
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China.
| | - Xuming Wu
- College of Physical Science and Technology, Lingnan Normal University, Zhanjiang 524048, China
| | - Shuang Qiao
- Beijing Computational Science Research Center, Beijing 100093, China
| | - Guoying Gao
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China.
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Li L, Zhang S, Hu G, Guo L, Wei T, Qin W, Xiang B, Zeng C, Zhang Z, Cui P. Converting a Monolayered NbSe 2 into an Ising Superconductor with Nontrivial Band Topology via Physical or Chemical Pressuring. NANO LETTERS 2022; 22:6767-6774. [PMID: 35930622 DOI: 10.1021/acs.nanolett.2c02422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Two-dimensional transition metal dichalcogenides possessing superconductivity and strong spin-orbit coupling exhibit high in-plane upper critical fields due to Ising pairing. Yet to date, whether such systems can become topological Ising superconductors remains to be materialized. Here we show that monolayered NbSe2 can be converted into Ising superconductors with nontrivial band topology via physical or chemical pressuring. Using first-principles calculations, we first demonstrate that a hydrostatic pressure higher than 2.5 GPa can induce a p-d band inversion, rendering nontrivial band topology to NbSe2. We then illustrate that Te-doping can function as chemical pressuring in inducing nontrivial topology in NbSe2-xTex with x ≥ 0.8, due to a larger atomic radius and stronger spin-orbit coupling of Te. We also evaluate the upper critical fields within both approaches, confirming the enhanced Ising superconductivity nature, as experimentally observed. Our findings may prove to be instrumental in material realization of topological Ising superconductivity in two-dimensional systems.
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Affiliation(s)
- Leiqiang Li
- International Center for Quantum Design of Functional Materials (ICQD), and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Shunhong Zhang
- International Center for Quantum Design of Functional Materials (ICQD), and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Guojing Hu
- Department of Materials Science & Engineering, CAS Key Lab of Materials for Energy Conversion, Anhui Laboratory of Advanced Photon Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Linhai Guo
- International Center for Quantum Design of Functional Materials (ICQD), and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Tong Wei
- International Center for Quantum Design of Functional Materials (ICQD), and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Wei Qin
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Bin Xiang
- Department of Materials Science & Engineering, CAS Key Lab of Materials for Energy Conversion, Anhui Laboratory of Advanced Photon Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
| | - Changgan Zeng
- International Center for Quantum Design of Functional Materials (ICQD), and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
| | - Zhenyu Zhang
- International Center for Quantum Design of Functional Materials (ICQD), and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
| | - Ping Cui
- International Center for Quantum Design of Functional Materials (ICQD), and CAS Center for Excellence in Quantum Information and Quantum Physics, 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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Wan W, Wickramaratne D, Dreher P, Harsh R, Mazin II, Ugeda MM. Nontrivial Doping Evolution of Electronic Properties in Ising-Superconducting Alloys. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2200492. [PMID: 35243698 DOI: 10.1002/adma.202200492] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 02/16/2022] [Indexed: 06/14/2023]
Abstract
Transition metal dichalcogenides offer unprecedented versatility to engineer 2D materials with tailored properties to explore novel structural and electronic phase transitions. In this work, the atomic-scale evolution of the electronic ground state of a monolayer of Nb1- δ Moδ Se2 across the entire alloy composition range (0 < δ < 1) is investigated using low-temperature (300 mK) scanning tunneling microscopy and spectroscopy (STM/STS). In particular, the atomic and electronic structure of this 2D alloy throughout the metal to semiconductor transition (monolayer NbSe2 to MoSe2 ) is studied. The measurements enable extraction of the effective doping of Mo atoms, the bandgap evolution and the band shifts, which are monotonic with δ. Furthermore, it is demonstrated that collective electronic phases (charge density wave and superconductivity) are remarkably robust against disorder and further shown that the superconducting TC changes non-monotonically with doping. This contrasting behavior in the normal and superconducting state is explained using first-principles calculations. Mo doping is shown to decrease the density of states at the Fermi level and the magnitude of pair-breaking spin fluctuations as a function of Mo content. These results paint a detailed picture of the electronic structure evolution in 2D TMD alloys, which is of utmost relevance for future 2D materials design.
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Affiliation(s)
- Wen Wan
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal 4, San Sebastián, 20018, Spain
| | - Darshana Wickramaratne
- Center for Computational Materials Science, U.S. Naval Research Laboratory, Washington, DC 20375, USA
| | - Paul Dreher
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal 4, San Sebastián, 20018, Spain
| | - Rishav Harsh
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal 4, San Sebastián, 20018, Spain
| | - Igor I Mazin
- Department of Physics and Astronomy, George Mason University, Fairfax, VA, 22030, USA
- Quantum Science and Engineering Center, George Mason University, Fairfax, VA, 22030, USA
| | - Miguel M Ugeda
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal 4, San Sebastián, 20018, Spain
- Centro de Física de Materiales (CSIC-UPV-EHU), Paseo Manuel de Lardizábal 5, San Sebastián, 20018, Spain
- Ikerbasque, Basque Foundation for Science, Bilbao, 48013, Spain
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