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arXiv · 1804.05719

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
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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.

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Sivan Refaely-Abramson, Diana Y. Qiu, Steven G. Louie, Jeffrey B. Neaton. 2018-07-21. Defect-induced modification of low-lying excitons and valley selectivity in monolayer transition metal dichalcogenides. https://doi.org/10.1103/physrevlett.121.167402

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