| Title | Robust circular polarization of indirect Q-K transitions in bilayer 3R-WS2 |
| Authors | Du, Luojun Zhang, Qian Zhang, Tingting Jia, Zhiyan Liang, Jing Liu, Gui-Bin Yang, Rong Shi, Dongxia Xiang, Jianyong Liu, Kaihui Sun, Zhipei Yao, Yugui Zhang, Qingming Zhang, Guangyu |
| Affiliation | Chinese Acad Sci, Beijing Natl Lab Condensed Matter Phys, Beijing 100190, Peoples R China Chinese Acad Sci, Inst Phys, Beijing 100190, Peoples R China Aalto Univ, Dept Elect & Nanoengn, Tietotie 3, FI-02150 Aalto, Finland Renmin Univ China, Dept Phys, Beijing 100872, Peoples R China Beijing Inst Technol, Sch Phys, Beijing Key Lab Nanophoton & Ultrafine Optoelect, Beijing 100081, Peoples R China Yanshan Univ, State Key Lab Metastable Mat Sci & Technol, Qinhuangdao 066004, Hebei, Peoples R China Peking Univ, Ctr Quantum Matter, Sch Phys, State Key Lab Mesoscop Phys, Beijing, Peoples R China Univ Chinese Acad Sci, Sch Phys Sci, Beijing 100190, Peoples R China Aalto Univ, QTF Ctr Excellence, Dept Appl Phys, FI-00076 Aalto, Finland Lanzhou Univ, Sch Phys Sci & Technol, Lanzhou 730000, Gansu, Peoples R China Songshan Lake Mat Lab, Dongguan 523808, Guangdong, Peoples R China |
| Issue Date | 2019 |
| Publisher | PHYSICAL REVIEW B |
| Abstract | Valley-contrasting Berry curvature and orbital magnetic moment have led to highly selective circular polarization of direct excitons at the K valleys in transition-metal dichalcogenides. In addition to K valleys, Q valleys, another critical point in the conduction band, also possess well-defined but distinct magnetic moment. Being akin to the direct excitons at K valleys, indirect excitons associated with Q (K) valleys in the conduction (valence) band could allow circular polarization in principle. Here, we report an experimental observation of the circular polarization of indirect Q-K transitions in noncentrosymmetric bilayer 3R-WS2. In stark contrast to the circular polarization of direct excitons which depolarizes with increasing lattice temperature, the circular polarization of indirect Q-K excitons is extremely robust and independent on the temperature. Such robust circular polarization can be understood as follows: the spin-orbit coupling in the Q valley is much stronger than that in the K point of the conduction band, significantly suppressing the temperature induced valley depolarization. Our results open up opportunities for exotic valleytronics and quantum information processing applications. |
| URI | http://hdl.handle.net/20.500.11897/553314 |
| ISSN | 2469-9950 |
| DOI | 10.1103/PhysRevB.100.161404 |
| Indexed | SCI(E) EI |
| Appears in Collections: | 物理学院 人工微结构和介观物理国家重点实验室 |
