中国物理B ›› 2021, Vol. 30 ›› Issue (1): 17303-.doi: 10.1088/1674-1056/abb65d

• • 上一篇    下一篇

  

  • 收稿日期:2020-07-16 修回日期:2020-08-17 接受日期:2020-09-09 出版日期:2020-12-17 发布日期:2020-12-30

Optical conductivity of twisted bilayer graphene near the magic angle

Lu Wen(文露), Zhiqiang Li(李志强), and Yan He(贺言)†   

  1. College of Physics, Sichuan University, Chengdu 610064, China
  • Received:2020-07-16 Revised:2020-08-17 Accepted:2020-09-09 Online:2020-12-17 Published:2020-12-30
  • Contact: Corresponding author. E-mail: heyan_ctp@scu.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 11874271 and 11874272).

Abstract: We theoretically study the band structure and optical conductivity of twisted bilayer graphene (TBG) near the magic angle considering the effects of lattice relaxation. We show that the optical conductivity spectrum is characterized by a series of peaks associated with the van Hove singularities in the band structure, and the peak energies evolve systematically with the twist angle. Lattice relaxation effects in TBG modify its band structure, especially the flat bands, which leads to significant shifts of the peaks in the optical conductivity. These results demonstrate that spectroscopic features in the optical conductivity can serve as fingerprints for exploring the band structure, band gap, and lattice relaxation in magic-angle TBG as well as identifying its rotation angle.

Key words: graphene, moir\'e superlattice, magic angle, optical conductivity

中图分类号:  (Superlattices)

  • 73.21.Cd
78.67.Wj (Optical properties of graphene) 73.22.Pr (Electronic structure of graphene) 73.25.+i (Surface conductivity and carrier phenomena)