中国物理B ›› 2022, Vol. 31 ›› Issue (10): 107301-107301.doi: 10.1088/1674-1056/ac5c3e

所属专题： SPECIAL TOPIC — Fabrication and manipulation of the second-generation quantum systems

• SPECIAL TOPIC—Fabrication and manipulation of the second-generation quantum systems • 上一篇    下一篇

Observation of multiple charge density wave phases in epitaxial monolayer 1T-VSe2 film

Junyu Zong(宗君宇)1, Yang Xie(谢阳)1, Qinghao Meng(孟庆豪)1, Qichao Tian(田启超)1, Wang Chen(陈望)1, Xuedong Xie(谢学栋)1, Shaoen Jin(靳少恩)1, Yongheng Zhang(张永衡)1, Li Wang(王利)2, Wei Ren(任伟)2, Jian Shen(沈健)2, Aixi Chen(陈爱喜)2, Pengdong Wang(王鹏栋)2, Fang-Sen Li(李坊森)2, Zhaoyang Dong(董召阳)3, Can Wang(王灿)1,4, Jian-Xin Li(李建新)1,4,†, and Yi Zhang(张翼)1,4,‡   

  1. 1. National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing 210093, China;
    2. Vacuum Interconnected Nanotech Workstation (Nano-X), Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences, Suzhou 215123, China;
    3. Department of Applied Physics, Nanjing University of Science and Technology, Nanjing 210094, China;
    4. Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
  • 收稿日期:2022-01-15 修回日期:2022-02-26 出版日期:2022-10-16 发布日期:2022-09-24
  • 通讯作者: Jian-Xin Li, Yi Zhang E-mail:jxli@nju.edu.cn;zhangyi@nju.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 92165205, 11790311, 12004172, 11774152, 11604366, and 11634007), the National Key Research and Development Program of China (Grant Nos. 2018YFA0306800 and 2016YFA0300401), the Program of High-Level Entrepreneurial and Innovative Talents Introduction of Jiangsu Province, the Jiangsu Planned Projects for Postdoctoral Research Funds (Grant No. 2020Z172), and the Natural Science Foundation of Jiangsu Province, China (Grant No. BK 20160397).

Observation of multiple charge density wave phases in epitaxial monolayer 1T-VSe2 film

Junyu Zong(宗君宇)1, Yang Xie(谢阳)1, Qinghao Meng(孟庆豪)1, Qichao Tian(田启超)1, Wang Chen(陈望)1, Xuedong Xie(谢学栋)1, Shaoen Jin(靳少恩)1, Yongheng Zhang(张永衡)1, Li Wang(王利)2, Wei Ren(任伟)2, Jian Shen(沈健)2, Aixi Chen(陈爱喜)2, Pengdong Wang(王鹏栋)2, Fang-Sen Li(李坊森)2, Zhaoyang Dong(董召阳)3, Can Wang(王灿)1,4, Jian-Xin Li(李建新)1,4,†, and Yi Zhang(张翼)1,4,‡   

  1. 1. National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing 210093, China;
    2. Vacuum Interconnected Nanotech Workstation (Nano-X), Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences, Suzhou 215123, China;
    3. Department of Applied Physics, Nanjing University of Science and Technology, Nanjing 210094, China;
    4. Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
  • Received:2022-01-15 Revised:2022-02-26 Online:2022-10-16 Published:2022-09-24
  • Contact: Jian-Xin Li, Yi Zhang E-mail:jxli@nju.edu.cn;zhangyi@nju.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 92165205, 11790311, 12004172, 11774152, 11604366, and 11634007), the National Key Research and Development Program of China (Grant Nos. 2018YFA0306800 and 2016YFA0300401), the Program of High-Level Entrepreneurial and Innovative Talents Introduction of Jiangsu Province, the Jiangsu Planned Projects for Postdoctoral Research Funds (Grant No. 2020Z172), and the Natural Science Foundation of Jiangsu Province, China (Grant No. BK 20160397).

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摘要： As a special order of electronic correlation induced by spatial modulation, the charge density wave (CDW) phenomena in condensed matters attract enormous research interests. Here, using scanning—tunneling microscopy in various temperatures, we discover a hidden incommensurate stripe-like CDW order besides the ($sqrt{7}$ × $sqrt{3}$) CDW phase at low-temperature of 4 K in the epitaxial monolayer 1T-VSe2} film. Combining the variable-temperature angle-resolved photoemission spectroscopic (ARPES) measurements, we discover a two-step transition of an anisotropic CDW gap structure that consists of two parts Δ1 and Δ2. The gap part Δ1 that closes around ～ 150 K is accompanied with the vanish of the ($sqrt{7}$ × $sqrt{3}$) CDW phase. While another momentum-dependent gap part Δ2 can survive up to ～ 340 K, and is suggested to the result of the incommensurate CDW phase. This two-step transition with anisotropic gap opening and the resulted evolution in ARPES spectra are corroborated by our theoretical calculation based on a phenomenological form for the self-energy containing a two-gap structure Δ1 + Δ2, which suggests different forming mechanisms between the ($sqrt{7}$ × $sqrt{3}$) and the incommensurate CDW phases. Our findings provide significant information and deep understandings on the CDW phases in monolayer 1T-VSe2} film as a two-dimensional (2D) material.

关键词: charge density waves, VSe2, band structures, STM, ARPES

Abstract: As a special order of electronic correlation induced by spatial modulation, the charge density wave (CDW) phenomena in condensed matters attract enormous research interests. Here, using scanning—tunneling microscopy in various temperatures, we discover a hidden incommensurate stripe-like CDW order besides the ($sqrt{7}$ × $sqrt{3}$) CDW phase at low-temperature of 4 K in the epitaxial monolayer 1T-VSe2} film. Combining the variable-temperature angle-resolved photoemission spectroscopic (ARPES) measurements, we discover a two-step transition of an anisotropic CDW gap structure that consists of two parts Δ1 and Δ2. The gap part Δ1 that closes around ～ 150 K is accompanied with the vanish of the ($sqrt{7}$ × $sqrt{3}$) CDW phase. While another momentum-dependent gap part Δ2 can survive up to ～ 340 K, and is suggested to the result of the incommensurate CDW phase. This two-step transition with anisotropic gap opening and the resulted evolution in ARPES spectra are corroborated by our theoretical calculation based on a phenomenological form for the self-energy containing a two-gap structure Δ1 + Δ2, which suggests different forming mechanisms between the ($sqrt{7}$ × $sqrt{3}$) and the incommensurate CDW phases. Our findings provide significant information and deep understandings on the CDW phases in monolayer 1T-VSe2} film as a two-dimensional (2D) material.

Key words: charge density waves, VSe2, band structures, STM, ARPES

中图分类号:  (Collective excitations (including excitons, polarons, plasmons and other charge-density excitations))

  • 73.20.Mf
73.20.At (Surface states, band structure, electron density of states) 73.61.-r (Electrical properties of specific thin films)