Chiral topological excitons in the monolayer transition metal dichalcogenides

H C Fu,Z R Gong,W Z Luo,Z F Jiang

doi:10.1038/srep42390

Abstract

We theoretically investigate the chiral topological excitons emerging in the monolayer transition metal dichalcogenides, where a bulk energy gap of valley excitons is opened up by a position dependent external magnetic field. We find two emerging chiral topological nontrivial excitons states, which exactly connects to the bulk topological properties, i.e., Chern number = 2. The dependence of the spectrum of the chiral topological excitons on the width of the magnetic field domain wall as well as the magnetic filed strength is numerically revealed. The chiral topological valley excitons are not only important to the excitonic transport due to prevention of the backscattering, but also give rise to the quantum coherent control in the optoelectronic applications.

Highlights

The topological states on the boundary or surface is one of the most fascinating phenomena in solid state physics
We shall theoretically investigate the chiral topological excitons emerging in the monolayer TMDs, where a bulk energy gap of valley excitons is opened up by a position dependent external magnetic field
Since the relative and center-of-mass motions are independent for the topological exciton, the optical dipole can be factorized as Di = Ai(D + + (−1 )i+1D−), where Ai = ∫ dxΦ+i (x) = ∫ dxΦ−i (x) are the integrals of the wavefunction profile and D± = e ⋅ ± p 0 are the optical dipole for the valley excitons ± k=0

Summary

Introduction

The topological states on the boundary or surface is one of the most fascinating phenomena in solid state physics. We shall theoretically investigate the chiral topological excitons emerging in the monolayer TMDs, where a bulk energy gap of valley excitons is opened up by a position dependent external magnetic field.

Results

Conclusion