1
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Li Y, Xu L, Liu G, Fang Y, Zheng H, Dai S, Li E, Zhu G, Zhang S, Liang S, Yang L, Huang F, Xi X, Liu Z, Xu N, Chen Y. Evidence of strong and mode-selective electron-phonon coupling in the topological superconductor candidate 2M-WS 2. Nat Commun 2024; 15:6235. [PMID: 39043689 PMCID: PMC11266404 DOI: 10.1038/s41467-024-50590-9] [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: 01/04/2024] [Accepted: 07/12/2024] [Indexed: 07/25/2024] Open
Abstract
The interaction between lattice vibrations and electrons plays a key role in various aspects of condensed matter physics - including electron hydrodynamics, strange metal behavior, and high-temperature superconductivity. In this study, we present systematic investigations using Raman scattering and angle-resolved photoemission spectroscopy (ARPES) to examine the phononic and electronic subsystems of the topological superconductor candidate 2M-WS2. Raman scattering exhibits an anomalous nonmonotonic temperature dependence of phonon linewidths, indicative of strong phonon-electron scattering over phonon-phonon scattering. The ARPES results demonstrate pronounced dispersion anomalies (kinks) at multiple binding energies within both bulk and topological surface states, indicating a robust and mode-selective coupling between the electronic states and various phonon modes. These experimental findings align with previous calculations of the Eliashberg function, providing a deeper understanding of the highest superconducting transition temperature observed in 2M-WS2 (8.8 K) among all transition metal dichalcogenides as induced by electron-phonon coupling. Furthermore, our results may offer valuable insights into other properties of 2M-WS2 and guide the search for high-temperature topological superconductors.
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Affiliation(s)
- Yiwei Li
- Institute for Advanced Studies (IAS), Wuhan University, Wuhan, China.
| | - Lixuan Xu
- Department of Physics, Hubei University, Wuhan, China
| | - Gan Liu
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China
| | - Yuqiang Fang
- School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Huijun Zheng
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, China
- ShanghaiTech Laboratory for Topological Physics, Shanghai, China
| | - Shenghao Dai
- Institute for Advanced Studies (IAS), Wuhan University, Wuhan, China
| | - Enting Li
- Institute for Advanced Studies (IAS), Wuhan University, Wuhan, China
| | - Guang Zhu
- Institute for Advanced Studies (IAS), Wuhan University, Wuhan, China
| | - Shihao Zhang
- School of Physics and Electronics, Hunan University, Changsha, China
| | - Shiheng Liang
- Department of Physics, Hubei University, Wuhan, China
| | - Lexian Yang
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, China
| | - Fuqiang Huang
- School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Xiaoxiang Xi
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing, China.
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China.
| | - Zhongkai Liu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, China.
- ShanghaiTech Laboratory for Topological Physics, Shanghai, China.
| | - Nan Xu
- Institute for Advanced Studies (IAS), Wuhan University, Wuhan, China.
- Wuhan Institute of Quantum Technology, Wuhan, China.
| | - Yulin Chen
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, China
- ShanghaiTech Laboratory for Topological Physics, Shanghai, China
- Department of Physics, University of Oxford, Oxford, UK
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2
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Plisson VM, Yao X, Wang Y, Varnavides G, Suslov A, Graf D, Choi ES, Yang HY, Wang Y, Romanelli M, McNamara G, Singh B, McCandless GT, Chan JY, Narang P, Tafti F, Burch KS. Engineering Anomalously Large Electron Transport in Topological Semimetals. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2310944. [PMID: 38470991 DOI: 10.1002/adma.202310944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 02/28/2024] [Indexed: 03/14/2024]
Abstract
Anomalous transport of topological semimetals has generated significant interest for applications in optoelectronics, nanoscale devices, and interconnects. Understanding the origin of novel transport is crucial to engineering the desired material properties, yet their orders of magnitude higher transport than single-particle mobilities remain unexplained. This work demonstrates the dramatic mobility enhancements result from phonons primarily returning momentum to electrons due to phonon-electron dominating over phonon-phonon scattering. Proving this idea, proposed by Peierls in 1932, requires tuning electron and phonon dispersions without changing symmetry, topology, or disorder. This is achieved by combining de Haas - van Alphen (dHvA), electron transport, Raman scattering, and first-principles calculations in the topological semimetals MX2 (M = Nb, Ta and X = Ge, Si). Replacing Ge with Si brings the transport mobilities from an order magnitude larger than single particle ones to nearly balanced. This occurs without changing the crystal structure or topology and with small differences in disorder or Fermi surface. Simultaneously, Raman scattering and first-principles calculations establish phonon-electron dominated scattering only in the MGe2 compounds. Thus, this study proves that phonon-drag is crucial to the transport properties of topological semimetals and provides insight to engineer these materials further.
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Affiliation(s)
| | - Xiaohan Yao
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | - Yaxian Wang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - George Varnavides
- College of Letters and Science, University of California Los Angeles, Los Angeles, California, 90095, USA
| | - Alexey Suslov
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida, 32310, USA
| | - David Graf
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida, 32310, USA
| | - Eun Sang Choi
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida, 32310, USA
| | - Hung-Yu Yang
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | - Yiping Wang
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | | | - Grant McNamara
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | - Birender Singh
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | - Gregory T McCandless
- Department of Chemistry and Biochemisty, Baylor University, Waco, TX, 76798, USA
| | - Julia Y Chan
- Department of Chemistry and Biochemisty, Baylor University, Waco, TX, 76798, USA
| | - Prineha Narang
- College of Letters and Science, University of California Los Angeles, Los Angeles, California, 90095, USA
| | - Fazel Tafti
- Department of Physics, Boston College, Chestnut Hill, MA, USA
| | - Kenneth S Burch
- Department of Physics, Boston College, Chestnut Hill, MA, USA
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3
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Okamura Y, Morimoto T, Ogawa N, Kaneko Y, Guo GY, Nakamura M, Kawasaki M, Nagaosa N, Tokura Y, Takahashi Y. Photovoltaic effect by soft phonon excitation. Proc Natl Acad Sci U S A 2022; 119:e2122313119. [PMID: 35344426 PMCID: PMC9169116 DOI: 10.1073/pnas.2122313119] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 02/20/2022] [Indexed: 11/22/2022] Open
Abstract
SignificanceThe quantum-mechanical geometric phase of electrons provides various phenomena such as the dissipationless photocurrent generation through the shift current mechanism. So far, the photocurrent generations are limited to above or near the band-gap photon energy, which contradicts the increasing demand of the low-energy photonic functionality. We demonstrate the photocurrent through the optical phonon excitations in ferroelectric BaTiO3 by using the terahertz light with photon energy far below the band gap. This photocurrent without electron-hole pair generation is never explained by the semiclassical treatment of electrons and only arises from the quantum-mechanical geometric phase. The observed photon-to-current conversion efficiency is as large as that for electronic excitation, which can be well accounted for by newly developed theoretical formulation of shift current.
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Affiliation(s)
- Yoshihiro Okamura
- Department of Applied Physics and Quantum Phase Electronics Center, University of Tokyo, Tokyo 113-8656, Japan
| | - Takahiro Morimoto
- Department of Applied Physics and Quantum Phase Electronics Center, University of Tokyo, Tokyo 113-8656, Japan
- PRESTO, Japan Science and Technology Agency, Tokyo 113-8656, Japan
| | - Naoki Ogawa
- Department of Applied Physics and Quantum Phase Electronics Center, University of Tokyo, Tokyo 113-8656, Japan
- RIKEN Center for Emergent Matter Science, Wako 351-0198, Japan
| | - Yoshio Kaneko
- RIKEN Center for Emergent Matter Science, Wako 351-0198, Japan
| | - Guang-Yu Guo
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
- Physics Division, National Center for Theoretical Sciences, Taipei 10617, Taiwan
| | - Masao Nakamura
- RIKEN Center for Emergent Matter Science, Wako 351-0198, Japan
| | - Masashi Kawasaki
- Department of Applied Physics and Quantum Phase Electronics Center, University of Tokyo, Tokyo 113-8656, Japan
- RIKEN Center for Emergent Matter Science, Wako 351-0198, Japan
| | - Naoto Nagaosa
- Department of Applied Physics and Quantum Phase Electronics Center, University of Tokyo, Tokyo 113-8656, Japan
- RIKEN Center for Emergent Matter Science, Wako 351-0198, Japan
| | - Yoshinori Tokura
- Department of Applied Physics and Quantum Phase Electronics Center, University of Tokyo, Tokyo 113-8656, Japan
- RIKEN Center for Emergent Matter Science, Wako 351-0198, Japan
- Tokyo College, University of Tokyo, Tokyo 113-8656, Japan
| | - Youtarou Takahashi
- Department of Applied Physics and Quantum Phase Electronics Center, University of Tokyo, Tokyo 113-8656, Japan
- RIKEN Center for Emergent Matter Science, Wako 351-0198, Japan
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