1
|
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.
Collapse
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
| |
Collapse
|
2
|
Multiple fermion scattering in the weakly coupled spin-chain compound YbAlO 3. Nat Commun 2021; 12:3599. [PMID: 34127661 PMCID: PMC8203633 DOI: 10.1038/s41467-021-23585-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 04/30/2021] [Indexed: 11/29/2022] Open
Abstract
The Heisenberg antiferromagnetic spin-1/2 chain, originally introduced almost a century ago, is one of the best studied models in quantum mechanics due to its exact solution, but nevertheless it continues to present new discoveries. Its low-energy physics is described by the Tomonaga-Luttinger liquid of spinless fermions, similar to the conduction electrons in one-dimensional metals. In this work we investigate the Heisenberg spin-chain compound YbAlO3 and show that the weak interchain coupling causes Umklapp scattering between the left- and right-moving fermions and stabilizes an incommensurate spin-density wave order at q = 2kF under finite magnetic fields. These Umklapp processes open a route to multiple coherent scattering of fermions, which results in the formation of satellites at integer multiples of the incommensurate fundamental wavevector Q = nq. Our work provides surprising and profound insight into bandstructure control for emergent fermions in quantum materials, and shows how neutron diffraction can be applied to investigate the phenomenon of coherent multiple scattering in metals through the proxy of quantum magnetic systems. A field-induced incommensurate spin density wave order was observed in the spin-chain material YbAlO3; however, its mechanism is not fully understood. Here, using neutron scattering and numerical calculations, the authors propose a mechanism based on multiple fermion scattering caused by weak inter-chain coupling.
Collapse
|
3
|
Iida K, Yoshida H, Okabe H, Katayama N, Ishii Y, Koda A, Inamura Y, Murai N, Ishikado M, Kadono R, Kajimoto R. Quantum magnetisms in uniform triangular lattices Li 2AMo 3O 8 (A = In, Sc). Sci Rep 2019; 9:1826. [PMID: 30755692 PMCID: PMC6372599 DOI: 10.1038/s41598-018-36123-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 11/07/2018] [Indexed: 12/03/2022] Open
Abstract
Molecular based spin-1/2 triangular lattice systems such as LiZn2Mo3O8 have attracted research interest. Distortions, defects, and intersite disorder are suppressed in such molecular-based magnets, and intrinsic geometrical frustration gives rise to unconventional and unexpected ground states. Li2AMo3O8 (A = In or Sc) is such a compound where spin-1/2 Mo3O13 clusters in place of Mo ions form the uniform triangular lattice. Their ground states are different according to the A site. Li2InMo3O8 undergoes conventional 120° long-range magnetic order below TN = 12 K whereas isomorphic Li2ScMo3O8 exhibits no long-range magnetic order down to 0.5 K. Here, we report exotic magnetisms in Li2InMo3O8 and Li2ScMo3O8 investigated by muon spin rotation (μSR) and inelastic neutron scattering (INS) spectroscopies using polycrystalline samples. Li2InMo3O8 and Li2ScMo3O8 show completely different behaviors observed in both μSR and INS measurements, representing their different ground states. Li2InMo3O8 exhibits spin wave excitation which is quantitatively described by the nearest neighbor anisotropic Heisenberg model based on the 120° spin structure. In contrast, Li2ScMo3O8 undergoes short-range magnetic order below 4 K with quantum-spin-liquid-like magnetic fluctuations down to the base temperature. Origin of the different ground states is discussed in terms of anisotropies of crystal structures and magnetic interactions.
Collapse
Affiliation(s)
- Kazuki Iida
- Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society (CROSS), Tokai, Ibaraki, 319-1106, Japan.
| | - Hiroyuki Yoshida
- Department of Physics, Faculty of Science, Hokkaido University, Sapporo, Hokkaido, 060-0810, Japan
| | - Hirotaka Okabe
- Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tokai, Ibaraki, 319-1106, Japan
| | - Naoyuki Katayama
- Department of Applied Physics, Nagoya University, Nagoya, Aichi, 464-8603, Japan
| | - Yuto Ishii
- Department of Physics, Faculty of Science, Hokkaido University, Sapporo, Hokkaido, 060-0810, Japan
| | - Akihiro Koda
- Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tokai, Ibaraki, 319-1106, Japan
- Department of Materials Structure Science, Sokendai (The Graduate University for Advanced Studies), Tsukuba, Ibaraki, 305-0801, Japan
| | - Yasuhiro Inamura
- J-PARC Center, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki, 319-1195, Japan
| | - Naoki Murai
- J-PARC Center, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki, 319-1195, Japan
| | - Motoyuki Ishikado
- Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society (CROSS), Tokai, Ibaraki, 319-1106, Japan
| | - Ryosuke Kadono
- Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tokai, Ibaraki, 319-1106, Japan
- Department of Materials Structure Science, Sokendai (The Graduate University for Advanced Studies), Tsukuba, Ibaraki, 305-0801, Japan
| | - Ryoichi Kajimoto
- J-PARC Center, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki, 319-1195, Japan
| |
Collapse
|
4
|
Savary L, Balents L. Quantum spin liquids: a review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2017; 80:016502. [PMID: 27823986 DOI: 10.1088/0034-4885/80/1/016502] [Citation(s) in RCA: 293] [Impact Index Per Article: 41.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Quantum spin liquids may be considered 'quantum disordered' ground states of spin systems, in which zero-point fluctuations are so strong that they prevent conventional magnetic long-range order. More interestingly, quantum spin liquids are prototypical examples of ground states with massive many-body entanglement, which is of a degree sufficient to render these states distinct phases of matter. Their highly entangled nature imbues quantum spin liquids with unique physical aspects, such as non-local excitations, topological properties, and more. In this review, we discuss the nature of such phases and their properties based on paradigmatic models and general arguments, and introduce theoretical technology such as gauge theory and partons, which are conveniently used in the study of quantum spin liquids. An overview is given of the different types of quantum spin liquids and the models and theories used to describe them. We also provide a guide to the current status of experiments in relation to study quantum spin liquids, and to the diverse probes used therein.
Collapse
Affiliation(s)
- Lucile Savary
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | | |
Collapse
|
5
|
Abstract
Frustrated magnets are materials in which localized magnetic moments, or spins, interact through competing exchange interactions that cannot be simultaneously satisfied, giving rise to a large degeneracy of the system ground state. Under certain conditions, this can lead to the formation of fluid-like states of matter, so-called spin liquids, in which the constituent spins are highly correlated but still fluctuate strongly down to a temperature of absolute zero. The fluctuations of the spins in a spin liquid can be classical or quantum and show remarkable collective phenomena such as emergent gauge fields and fractional particle excitations. This exotic behaviour is now being uncovered in the laboratory, providing insight into the properties of spin liquids and challenges to the theoretical description of these materials.
Collapse
Affiliation(s)
- Leon Balents
- Kavli Institute for Theoretical Physics, University of California, Santa Barbara, Santa Barbara, California 93106, USA.
| |
Collapse
|