Strongly distinct electrical response between circular and valley polarization in bilayer transition metal dichalcogenides

Research output: Contribution to journalArticleScientificpeer-review

Researchers

  • Luojun Du

  • Mengzhou Liao
  • Gui Bin Liu
  • Qinqin Wang
  • Rong Yang
  • Dongxia Shi
  • Yugui Yao
  • Guangyu Zhang

Research units

  • Chinese Academy of Sciences
  • Beijing Institute of Technology
  • University of Chinese Academy of Sciences
  • Collaborative Innovation Center of Quantum Matter
  • Songshan Lake Materials Laboratory

Abstract

We introduce a physical model to describe the influence of a perpendicular electric field on circular polarization (CP) and valley polarization (VP) in bilayer transition metal dichalcogenides. Our results uncover that electric-field-dependent CP and VP are quite distinct from each other. The dependence of CP on the electric field harbors a W pattern and possesses the minimum when the potential energy difference between the two layers is equal to the strength of spin-orbit coupling. Such dependence of CP stems from the modulation of energy cost for interlayer hopping and spin-dependent layer polarization. In contrast, VP is strictly absent in primitive bilayers and increases monotonically with increasing strength of electric field, resulting from the continuous variation of valley magnetic moments and inversion-symmetry breaking. Our model elaborates well the recent experimental observations for which the origin is under debate. Moreover, we demonstrate that the manipulation of layer and valley pseudospin is fully tunable by perpendicular electric fields, paving the way for prospects in electrical control of exotic layer-valleytronics.

Details

Original languageEnglish
Article number195415
JournalPhysical Review B
Volume99
Issue number19
Publication statusPublished - 10 May 2019
MoE publication typeA1 Journal article-refereed

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