1
|
Xue G, Qin B, Ma C, Yin P, Liu C, Liu K. Large-Area Epitaxial Growth of Transition Metal Dichalcogenides. Chem Rev 2024. [PMID: 39132950 DOI: 10.1021/acs.chemrev.3c00851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/13/2024]
Abstract
Over the past decade, research on atomically thin two-dimensional (2D) transition metal dichalcogenides (TMDs) has expanded rapidly due to their unique properties such as high carrier mobility, significant excitonic effects, and strong spin-orbit couplings. Considerable attention from both scientific and industrial communities has fully fueled the exploration of TMDs toward practical applications. Proposed scenarios, such as ultrascaled transistors, on-chip photonics, flexible optoelectronics, and efficient electrocatalysis, critically depend on the scalable production of large-area TMD films. Correspondingly, substantial efforts have been devoted to refining the synthesizing methodology of 2D TMDs, which brought the field to a stage that necessitates a comprehensive summary. In this Review, we give a systematic overview of the basic designs and significant advancements in large-area epitaxial growth of TMDs. We first sketch out their fundamental structures and diverse properties. Subsequent discussion encompasses the state-of-the-art wafer-scale production designs, single-crystal epitaxial strategies, and techniques for structure modification and postprocessing. Additionally, we highlight the future directions for application-driven material fabrication and persistent challenges, aiming to inspire ongoing exploration along a revolution in the modern semiconductor industry.
Collapse
Affiliation(s)
- Guodong Xue
- State Key Laboratory for Mesoscopic Physics, Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Biao Qin
- State Key Laboratory for Mesoscopic Physics, Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Chaojie Ma
- State Key Laboratory for Mesoscopic Physics, Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Peng Yin
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Department of Physics, Renmin University of China, Beijing 100872, China
| | - Can Liu
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Department of Physics, Renmin University of China, Beijing 100872, China
| | - Kaihui Liu
- State Key Laboratory for Mesoscopic Physics, Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
- International Centre for Quantum Materials, Collaborative Innovation Centre of Quantum Matter, Peking University, Beijing 100871, China
- Songshan Lake Materials Laboratory, Dongguan 523808, China
| |
Collapse
|
2
|
Qiu Z, Han Y, Noori K, Chen Z, Kashchenko M, Lin L, Olsen T, Li J, Fang H, Lyu P, Telychko M, Gu X, Adam S, Quek SY, Rodin A, Castro Neto AH, Novoselov KS, Lu J. Evidence for electron-hole crystals in a Mott insulator. NATURE MATERIALS 2024; 23:1055-1062. [PMID: 38831130 DOI: 10.1038/s41563-024-01910-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 04/30/2024] [Indexed: 06/05/2024]
Abstract
The coexistence of correlated electron and hole crystals enables the realization of quantum excitonic states, capable of hosting counterflow superfluidity and topological orders with long-range quantum entanglement. Here we report evidence for imbalanced electron-hole crystals in a doped Mott insulator, namely, α-RuCl3, through gate-tunable non-invasive van der Waals doping from graphene. Real-space imaging via scanning tunnelling microscopy reveals two distinct charge orderings at the lower and upper Hubbard band energies, whose origin is attributed to the correlation-driven honeycomb hole crystal composed of hole-rich Ru sites and rotational-symmetry-breaking paired electron crystal composed of electron-rich Ru-Ru bonds, respectively. Moreover, a gate-induced transition of electron-hole crystals is directly visualized, further corroborating their nature as correlation-driven charge crystals. The realization and atom-resolved visualization of imbalanced electron-hole crystals in a doped Mott insulator opens new doors in the search for correlated bosonic states within strongly correlated materials.
Collapse
Affiliation(s)
- Zhizhan Qiu
- Institute for Functional Intelligent Materials, National University of Singapore, Singapore, Singapore
| | - Yixuan Han
- Department of Chemistry, National University of Singapore, Singapore, Singapore
| | - Keian Noori
- Institute for Functional Intelligent Materials, National University of Singapore, Singapore, Singapore
- Centre for Advanced 2D Materials (CA2DM), National University of Singapore, Singapore, Singapore
| | - Zhaolong Chen
- Institute for Functional Intelligent Materials, National University of Singapore, Singapore, Singapore
- School of Advanced Materials, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Mikhail Kashchenko
- Programmable Functional Materials Lab, Brain and Consciousness Research Center, Moscow, Russia
- Center for Photonics and 2D Materials, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Li Lin
- Institute for Functional Intelligent Materials, National University of Singapore, Singapore, Singapore
- School of Materials Science and Engineering, Peking University, Beijing, China
| | - Thomas Olsen
- CAMD, Department of Physics, Technical university of Denmark, Lyngby, Denmark
| | - Jing Li
- School of Chemistry, Beihang University, Beijing, China
| | - Hanyan Fang
- Department of Chemistry, National University of Singapore, Singapore, Singapore
| | - Pin Lyu
- Department of Chemistry, National University of Singapore, Singapore, Singapore
| | - Mykola Telychko
- Department of Chemistry, National University of Singapore, Singapore, Singapore
| | - Xingyu Gu
- Centre for Advanced 2D Materials (CA2DM), National University of Singapore, Singapore, Singapore
- Department of Physics, National University of Singapore, Singapore, Singapore
| | - Shaffique Adam
- Centre for Advanced 2D Materials (CA2DM), National University of Singapore, Singapore, Singapore
- Department of Physics, National University of Singapore, Singapore, Singapore
- Yale-NUS College, Singapore, Singapore
- Department of Materials Science & Engineering, National University of Singapore, Singapore, Singapore
| | - Su Ying Quek
- Centre for Advanced 2D Materials (CA2DM), National University of Singapore, Singapore, Singapore
- Department of Physics, National University of Singapore, Singapore, Singapore
- Department of Materials Science & Engineering, National University of Singapore, Singapore, Singapore
- NUS Graduate School, Integrative Sciences and Engineering Programme, National University of Singapore, Singapore, Singapore
| | - Aleksandr Rodin
- Centre for Advanced 2D Materials (CA2DM), National University of Singapore, Singapore, Singapore
- Yale-NUS College, Singapore, Singapore
| | - A H Castro Neto
- Institute for Functional Intelligent Materials, National University of Singapore, Singapore, Singapore
- Centre for Advanced 2D Materials (CA2DM), National University of Singapore, Singapore, Singapore
- Department of Materials Science & Engineering, National University of Singapore, Singapore, Singapore
| | - Kostya S Novoselov
- Institute for Functional Intelligent Materials, National University of Singapore, Singapore, Singapore.
- Department of Materials Science & Engineering, National University of Singapore, Singapore, Singapore.
| | - Jiong Lu
- Institute for Functional Intelligent Materials, National University of Singapore, Singapore, Singapore.
- Department of Chemistry, National University of Singapore, Singapore, Singapore.
- Centre for Advanced 2D Materials (CA2DM), National University of Singapore, Singapore, Singapore.
| |
Collapse
|
3
|
Torbatian Z, Novko D. Plasmon Excitations across the Charge-Density-Wave Transition in Single-Layer TiSe 2. J Phys Chem Lett 2024; 15:6045-6050. [PMID: 38819234 DOI: 10.1021/acs.jpclett.4c01034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2024]
Abstract
1T-TiSe2 is believed to possess a soft electronic mode, i.e., plasmon or exciton, that might be responsible for the exciton condensation and charge-density-wave (CDW) transition. Here, we explore collective electronic excitations in single-layer 1T-TiSe2 by using the ab initio electromagnetic linear response and unveil intricate scattering pathways of the two-dimensional (2D) plasmon mode near the CDW phase. We found the dominant role of plasmon-phonon scattering, which in combination with the CDW gap excitations leads to the anomalous temperature dependence of the plasmon line width across the CDW transition. Below the transition temperature TCDW a strong hybridization between the 2D plasmon and CDW excitations is obtained. These optical features are highly tunable due to temperature-dependent CDW-related modifications of electronic structure and electron-phonon coupling and make CDW-bearing systems potentially interesting for applications in optoelectronics and low-loss plasmonics.
Collapse
Affiliation(s)
- Zahra Torbatian
- School of Nano Science, Institute for Research in Fundamental Sciences (IPM), 19395-5531 Tehran, Iran
| | - Dino Novko
- Centre for Advanced Laser Techniques, Institute of Physics, 10000 Zagreb, Croatia
- Donostia International Physics Center (DIPC), 20018 Donostia-San Sebastián, Spain
| |
Collapse
|
4
|
Xu YJ, Cao G, Li QY, Xue CL, Zhao WM, Wang QW, Dou LG, Du X, Meng YX, Wang YK, Gao YH, Jia ZY, Li W, Ji L, Li FS, Zhang Z, Cui P, Xing D, Li SC. Realization of monolayer ZrTe 5 topological insulators with wide band gaps. Nat Commun 2024; 15:4784. [PMID: 38839772 PMCID: PMC11153644 DOI: 10.1038/s41467-024-49197-x] [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: 11/24/2023] [Accepted: 05/28/2024] [Indexed: 06/07/2024] Open
Abstract
Two-dimensional topological insulators hosting the quantum spin Hall effect have application potential in dissipationless electronics. To observe the quantum spin Hall effect at elevated temperatures, a wide band gap is indispensable to efficiently suppress bulk conduction. Yet, most candidate materials exhibit narrow or even negative band gaps. Here, via elegant control of van der Waals epitaxy, we have successfully grown monolayer ZrTe5 on a bilayer graphene/SiC substrate. The epitaxial ZrTe5 monolayer crystalizes in two allotrope isomers with different intralayer alignments of ZrTe3 prisms. Our scanning tunneling microscopy/spectroscopy characterization unveils an intrinsic full band gap as large as 254 meV and one-dimensional edge states localized along the periphery of the ZrTe5 monolayer. First-principles calculations further confirm that the large band gap originates from strong spin-orbit coupling, and the edge states are topologically nontrivial. These findings thus provide a highly desirable material platform for the exploration of the high-temperature quantum spin Hall effect.
Collapse
Affiliation(s)
- Yong-Jie Xu
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, China
| | - Guohua Cao
- International Center for Quantum Design of Functional Materials (ICQD), University of Science and Technology of China, Hefei, China
| | - Qi-Yuan Li
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, China
| | - Cheng-Long Xue
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, China
| | - Wei-Min Zhao
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, China
| | - Qi-Wei Wang
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, China
| | - Li-Guo Dou
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, China
| | - Xuan Du
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, China
| | - Yu-Xin Meng
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, China
| | - Yuan-Kun Wang
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, China
| | - Yu-Hang Gao
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, China
| | - Zhen-Yu Jia
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, China
| | - Wei Li
- Vacuum Interconnected Nanotech Workstation, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, China
| | - Lianlian Ji
- Vacuum Interconnected Nanotech Workstation, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, China
| | - Fang-Sen Li
- Vacuum Interconnected Nanotech Workstation, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, China
| | - Zhenyu Zhang
- International Center for Quantum Design of Functional Materials (ICQD), University of Science and Technology of China, Hefei, China
- Hefei National Laboratory, Hefei, China
| | - Ping Cui
- International Center for Quantum Design of Functional Materials (ICQD), University of Science and Technology of China, Hefei, China.
- Hefei National Laboratory, Hefei, China.
| | - Dingyu Xing
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China
| | - Shao-Chun Li
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, China.
- Hefei National Laboratory, Hefei, China.
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China.
- Jiangsu Provincial Key Laboratory for Nanotechnology, Nanjing University, Nanjing, China.
| |
Collapse
|
5
|
Haque SRU, Michael MH, Zhu J, Zhang Y, Windgätter L, Latini S, Wakefield JP, Zhang GF, Zhang J, Rubio A, Checkelsky JG, Demler E, Averitt RD. Terahertz parametric amplification as a reporter of exciton condensate dynamics. NATURE MATERIALS 2024; 23:796-802. [PMID: 38172546 DOI: 10.1038/s41563-023-01755-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 11/06/2023] [Indexed: 01/05/2024]
Abstract
Condensates are a hallmark of emergence in quantum materials such as superconductors and charge density waves. Excitonic insulators are an intriguing addition to this library, exhibiting spontaneous condensation of electron-hole pairs. However, condensate observables can be obscured through parasitic coupling to the lattice. Here we employ nonlinear terahertz spectroscopy to disentangle such obscurants through measurement of the quantum dynamics. We target Ta2NiSe5, a putative room-temperature excitonic insulator in which electron-lattice coupling dominates the structural transition (Tc = 326 K), hindering identification of excitonic correlations. A pronounced increase in the terahertz reflectivity manifests following photoexcitation and exhibits a Bose-Einstein condensation-like temperature dependence well below the Tc, suggesting an approach to monitor the exciton condensate dynamics. Nonetheless, dynamic condensate-phonon coupling remains as evidenced by peaks in the enhanced reflectivity spectrum at select infrared-active phonon frequencies, indicating that parametric reflectivity enhancement arises from phonon squeezing. Our results highlight that coherent dynamics can drive parametric stimulated emission.
Collapse
Affiliation(s)
- Sheikh Rubaiat Ul Haque
- Department of Physics, University of California San Diego, La Jolla, CA, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | | | - Junbo Zhu
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Yuan Zhang
- Department of Physics, University of California San Diego, La Jolla, CA, USA
| | - Lukas Windgätter
- Max Planck Institute for the Structure and Dynamics of Matter (MPSD), Hamburg, Germany
| | - Simone Latini
- Max Planck Institute for the Structure and Dynamics of Matter (MPSD), Hamburg, Germany
| | - Joshua P Wakefield
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Gu-Feng Zhang
- Department of Physics, University of California San Diego, La Jolla, CA, USA
| | - Jingdi Zhang
- Department of Physics, University of California San Diego, La Jolla, CA, USA
- Department of Physics, The Hong Kong University of Science and Technology, Hongkong, China
| | - Angel Rubio
- Max Planck Institute for the Structure and Dynamics of Matter (MPSD), Hamburg, Germany
- Center for Computational Quantum Physics, The Flatiron Institute, New York, NY, USA
| | - Joseph G Checkelsky
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Eugene Demler
- Department of Physics, Harvard University, Cambridge, MA, USA
- Institute for Theoretical Physics, ETH Zürich, Zürich, Switzerland
| | - Richard D Averitt
- Department of Physics, University of California San Diego, La Jolla, CA, USA.
| |
Collapse
|
6
|
Rhee TG, Lam NH, Kim YG, Gu M, Hwang J, Bostwick A, Mo SK, Chun SH, Kim J, Chang YJ, Choi BK. Emergence of two distinct phase transitions in monolayer CoSe 2 on graphene. NANO CONVERGENCE 2024; 11:21. [PMID: 38789878 PMCID: PMC11126552 DOI: 10.1186/s40580-024-00427-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 05/09/2024] [Indexed: 05/26/2024]
Abstract
Dimensional modifications play a crucial role in various applications, especially in the context of device miniaturization, giving rise to novel quantum phenomena. The many-body dynamics induced by dimensional modifications, including electron-electron, electron-phonon, electron-magnon and electron-plasmon coupling, are known to significantly affect the atomic and electronic properties of the materials. By reducing the dimensionality of orthorhombic CoSe2 and forming heterostructure with bilayer graphene using molecular beam epitaxy, we unveil the emergence of two types of phase transitions through angle-resolved photoemission spectroscopy and scanning tunneling microscopy measurements. We disclose that the 2 × 1 superstructure is associated with charge density wave induced by Fermi surface nesting, characterized by a transition temperature of 340 K. Additionally, another phase transition at temperature of 160 K based on temperature dependent gap evolution are observed with renormalized electronic structure induced by electron-boson coupling. These discoveries of the electronic and atomic modifications, influenced by electron-electron and electron-boson interactions, underscore that many-body physics play significant roles in understanding low-dimensional properties of non-van der Waals Co-chalcogenides and related heterostructures.
Collapse
Affiliation(s)
- Tae Gyu Rhee
- Department of Physics, University of Seoul, Seoul, 02504, Korea
- Department of Smart Cities, University of Seoul, Seoul, 02504, Korea
| | - Nguyen Huu Lam
- Department of Physics, University of Ulsan, Ulsan, 44610, Korea
| | - Yeong Gwang Kim
- Department of Physics, University of Seoul, Seoul, 02504, Korea
- Department of Smart Cities, University of Seoul, Seoul, 02504, Korea
| | - Minseon Gu
- Department of Physics, University of Seoul, Seoul, 02504, Korea
| | - Jinwoong Hwang
- Department of Physics, Institute of Quantum Convergence Technology, Kangwon National University, Chuncheon, 24341, Korea
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Aaron Bostwick
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Sung-Kwan Mo
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Seung-Hyun Chun
- Department of Physics, Sejong University, Seoul, 05006, Korea
| | - Jungdae Kim
- Department of Physics, University of Ulsan, Ulsan, 44610, Korea.
| | - Young Jun Chang
- Department of Physics, University of Seoul, Seoul, 02504, Korea.
- Department of Smart Cities, University of Seoul, Seoul, 02504, Korea.
- Department of Intelligent Semiconductor Engineering, University of Seoul, Seoul, 02504, Korea.
| | - Byoung Ki Choi
- Department of Physics, University of Seoul, Seoul, 02504, Korea.
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
| |
Collapse
|
7
|
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.
Collapse
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.
| |
Collapse
|
8
|
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
|
9
|
Antonelli T, Rajan A, Watson MD, Soltani S, Houghton J, Siemann GR, Zivanovic A, Bigi C, Edwards B, King PDC. Controlling the Charge Density Wave Transition in Single-Layer TiTe 2xSe 2(1-x) Alloys by Band Gap Engineering. NANO LETTERS 2024; 24:215-221. [PMID: 38117702 PMCID: PMC10786161 DOI: 10.1021/acs.nanolett.3c03776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 12/13/2023] [Accepted: 12/14/2023] [Indexed: 12/22/2023]
Abstract
Closing the band gap of a semiconductor into a semimetallic state gives a powerful potential route to tune the electronic energy gains that drive collective phases like charge density waves (CDWs) and excitonic insulator states. We explore this approach for the controversial CDW material monolayer (ML) TiSe2 by engineering its narrow band gap to the semimetallic limit of ML-TiTe2. Using molecular beam epitaxy, we demonstrate the growth of ML-TiTe2xSe2(1-x) alloys across the entire compositional range and unveil how the (2 × 2) CDW instability evolves through the normal state semiconductor-semimetal transition via in situ angle-resolved photoemission spectroscopy. Through model electronic structure calculations, we identify how this tunes the relative strength of excitonic and Peierls-like coupling, demonstrating band gap engineering as a powerful method for controlling the microscopic mechanisms underpinning the formation of collective states in two-dimensional materials.
Collapse
Affiliation(s)
- Tommaso Antonelli
- SUPA, School of Physics and
AstronomyUniversity of St Andrews, St Andrews KY16 9SS, United Kingdom
| | - Akhil Rajan
- SUPA, School of Physics and
AstronomyUniversity of St Andrews, St Andrews KY16 9SS, United Kingdom
| | - Matthew D. Watson
- SUPA, School of Physics and
AstronomyUniversity of St Andrews, St Andrews KY16 9SS, United Kingdom
| | | | - Joe Houghton
- SUPA, School of Physics and
AstronomyUniversity of St Andrews, St Andrews KY16 9SS, United Kingdom
| | - Gesa-Roxanne Siemann
- SUPA, School of Physics and
AstronomyUniversity of St Andrews, St Andrews KY16 9SS, United Kingdom
| | - Andela Zivanovic
- SUPA, School of Physics and
AstronomyUniversity of St Andrews, St Andrews KY16 9SS, United Kingdom
| | - Chiara Bigi
- SUPA, School of Physics and
AstronomyUniversity of St Andrews, St Andrews KY16 9SS, United Kingdom
| | - Brendan Edwards
- SUPA, School of Physics and
AstronomyUniversity of St Andrews, St Andrews KY16 9SS, United Kingdom
| | - Phil D. C. King
- SUPA, School of Physics and
AstronomyUniversity of St Andrews, St Andrews KY16 9SS, United Kingdom
| |
Collapse
|
10
|
Li Y, Wan Q, Xu N. Recent Advances in Moiré Superlattice Systems by Angle-Resolved Photoemission Spectroscopy. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023:e2305175. [PMID: 37689836 DOI: 10.1002/adma.202305175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 08/16/2023] [Indexed: 09/11/2023]
Abstract
The last decade has witnessed a flourish in 2D materials including graphene and transition metal dichalcogenides (TMDs) as atomic-scale Legos. Artificial moiré superlattices via stacking 2D materials with a twist angle and/or a lattice mismatch have recently become a fertile playground exhibiting a plethora of emergent properties beyond their building blocks. These rich quantum phenomena stem from their nontrivial electronic structures that are effectively tuned by the moiré periodicity. Modern angle-resolved photoemission spectroscopy (ARPES) can directly visualize electronic structures with decent momentum, energy, and spatial resolution, thus can provide enlightening insights into fundamental physics in moiré superlattice systems and guides for designing novel devices. In this review, first, a brief introduction is given on advanced ARPES techniques and basic ideas of band structures in a moiré superlattice system. Then ARPES research results of various moiré superlattice systems are highlighted, including graphene on substrates with small lattice mismatches, twisted graphene/TMD moiré systems, and high-order moiré superlattice systems. Finally, it discusses important questions that remain open, challenges in current experimental investigations, and presents an outlook on this field of research.
Collapse
Affiliation(s)
- Yiwei Li
- Institute for Advanced Studies (IAS), Wuhan University, Wuhan, 430072, China
| | - Qiang Wan
- Institute for Advanced Studies (IAS), Wuhan University, Wuhan, 430072, China
| | - Nan Xu
- Institute for Advanced Studies (IAS), Wuhan University, Wuhan, 430072, China
- Wuhan Institute of Quantum Technology, Wuhan, 430206, China
| |
Collapse
|