Topological excitons in moir\'e MoTe$_2$/WSe$_2$ heterobilayers

TL;DR

This paper demonstrates that in moiré MoTe₂/WSe₂ heterobilayers, excitons can form topological flat bands, opening pathways to explore strongly correlated bosonic topological phases.

Contribution

It identifies a regime where excitons in moiré TMD heterobilayers form topological flat bands using time-dependent Hartree-Fock calculations.

Findings

Excitons inherit the topology of Chern bands in moiré TMDs.

A specific phase diagram regime hosts topological flat exciton bands.

Potential for realizing strongly correlated bosonic topological states.

Abstract

Due to the presence of flat Chern bands, moir\'e transition metal dichalcogenide (TMD) bilayers are a platform to realize strongly correlated topological phases of fermions such as fractional Chern insulators. TMDs are also known to host long-lived excitons, which inherit the topology of the underlying Chern bands. For the particular example of MoTe$_2$/WSe$_2$ heterobilayers we perform a time-dependent Hartree-Fock calculation to identify a regime in the phase diagram where the excitons themselves form a topological flat band. This paves a way towards realizing strongly correlated states of bosons in moir\'e TMDs.