Magneto-optical studies οf excitons in monolayer WSe₂
Ya-Ting Chang (張雅婷)1*, Ming-Yang Li (李明洋)2, Lain-Jong Li (李連忠)2, Daisuke Nakamura3, Shojiro Takeyama3, Hsiang-Lin Liu (劉祥麟)1
1Department of Physics, National Taiwan Normal University, Taipei 11677, Taiwan
2Physical Science and Engineering Division, King Abdullah University of Science & Technology, Thuwal 23955, Saudi Arabia
3Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
* presenting author:Ya-Ting Chang,
We present temperature and magnetic field dependences of optical absorption measurements in monolayer WSe2. The room temperature absorption features of A and B excitons as well as A and B band edges are observed at approximately 1.66, 2.08, 2.44, and 2.93 eV. With decreasing temperature, all absorption peaks shift to higher energy up to 0.08 eV. Furthermore, measurements in an applied magnetic field at 4.2 K reveal that the energies of charged and neutral excitons shift linearly with the magnetic field and the direction of the shifts is reversed for photons with opposite circular polarization. The Zeeman shift of charge and neutral excitons and A band edge is robust at approximately 0.15 meV/T. These findings advance our understanding of valley physics in monolayer WSe2 and provide a foundation for the technological development of valleytronics devices.

Keywords: transition metal dichacogenides, monolayer WSe2, magneto-optics, valley splitting