Defect-Induced Modification of Low-Lying Excitons and Valley Selectivity in Monolayer Transition Metal Dichalcogenides

Sivan Refaely-Abramson, Diana Y. Qiu, Steven G. Louie, Jeffrey B. Neaton

Research output: Contribution to journalArticlepeer-review

Abstract

We study the effect of point-defect chalcogen vacancies on the optical properties of monolayer transition metal dichalcogenides using ab initio GW and Bethe-Salpeter equation calculations. We find that chalcogen vacancies introduce unoccupied in-gap states and occupied resonant defect states within the quasiparticle continuum of the valence band. These defect states give rise to a number of strongly bound defect excitons and hybridize with excitons of the pristine system, reducing the valley-selective circular dichroism. Our results suggest a pathway to tune spin-valley polarization and other optical properties through defect engineering.

Original languageEnglish
Article number167402
Number of pages7
JournalPhysical review letters
Volume121
Issue number16
DOIs
StatePublished - 19 Oct 2018
Externally publishedYes

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