Giant Valley Coherence at Room Temperature in 3R WS2 with Broken Inversion Symmetry
Luojun Du,
Jian Tang,
Jing Liang,
Mengzhou Liao,
Zhiyan Jia,
Qinghua Zhang,
Yanchong Zhao,
Rong Yang,
Dongxia Shi,
Lin Gu,
Jianyong Xiang,
Kaihui Liu,
Zhipei Sun,
Guangyu Zhang
Affiliations
Luojun Du
Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; Department of Electronics and Nanoengineering, Aalto University, Tietotie 3, FI-02150, Finland
Jian Tang
Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
Jing Liang
State Key Laboratory for Mesoscopic Physics, Collaborative Innovation, Center of Quantum Matter, School of Physics, Peking University, Beijing, China
Mengzhou Liao
Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
Zhiyan Jia
State Key Laboratory for Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China
Qinghua Zhang
Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
Yanchong Zhao
Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
Rong Yang
Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
Dongxia Shi
Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; School of Physical Sciences, University of Chinese Academy of Science, Beijing 100190, China; Beijing Key Laboratory for Nanomaterials and Nanodevices, Beijing 100190, China
Lin Gu
Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
Jianyong Xiang
State Key Laboratory for Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China
Kaihui Liu
State Key Laboratory for Mesoscopic Physics, Collaborative Innovation, Center of Quantum Matter, School of Physics, Peking University, Beijing, China
Zhipei Sun
Department of Electronics and Nanoengineering, Aalto University, Tietotie 3, FI-02150, Finland; QTF Centre of Excellence, Department of Applied Physics, Aalto University, FI-00076 Aalto, Finland
Guangyu Zhang
Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; School of Physical Sciences, University of Chinese Academy of Science, Beijing 100190, China; Beijing Key Laboratory for Nanomaterials and Nanodevices, Beijing 100190, China; Songshan-Lake Materials Laboratory, Dongguan, 523808 Guangdong Province, China
Breaking the space-time symmetries in materials can markedly influence their electronic and optical properties. In 3R-stacked transition metal dichalcogenides, the explicitly broken inversion symmetry enables valley-contrasting Berry curvature and quantization of electronic angular momentum, providing an unprecedented platform for valleytronics. Here, we study the valley coherence of 3R WS2 large single-crystal with thicknesses ranging from monolayer to octalayer at room temperature. Our measurements demonstrate that both A and B excitons possess robust and thickness-independent valley coherence. The valley coherence of direct A (B) excitons can reach 0.742 (0.653) with excitation conditions on resonance with it. Such giant and thickness-independent valley coherence of large single-crystal 3R WS2 at room temperature would provide a firm foundation for quantum manipulation of the valley degree of freedom and practical application of valleytronics.
