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Group representations of exciton states and their derivation from first principles

ORAL

Abstract

Excitons play an essential role in the optical properties of semiconductors, especially in reduced-dimensional systems. Their symmetry characters are important ingredients that are relevant to selection rules for optical transition and other interactions. Here, we present a method to derive group representations of exciton states directly from ab initio GW-Bethe-Salpeter-equation calculations without any assumptions on the characters of the envelope functions. This method can be applied to study symmetry properties of Wannier and Frenkel excitons, as well as excitons arising from Mexican-hat quasiparticle bands or parallel valence and conduction bands (e.g. the C exciton in monolayer MoS2). The method gives definitive conclusion on the exciton-state splitting and degeneracy, mitigating uncertainties from numerical noises.

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Presenters

  • Jiawei Ruan

    University of California at Berkeley, and Lawrence Berkeley National Laboratory, University of California, Berkeley

Authors

  • Jiawei Ruan

    University of California at Berkeley, and Lawrence Berkeley National Laboratory, University of California, Berkeley

  • Zhenglu Li

    Department of Physics, University of California, Berkeley, UC Berkeley & Lawrence Berkeley National Laboratory, University of California at Berkeley, and Lawrence Berkeley National Laboratory, University of California at Berkeley and Lawrence Berkeley National Laboratory, Lawrence Berkeley National Laboratory, University of California, Berkeley, Lawrence Berkeley National Laboratory and University of California at Berkeley, Department of physics, University of California at Berkeley, Berkeley, California

  • Chin Shen Ong

    University of California at Berkeley, and Lawrence Berkeley National Laboratory, Department of physics, University of California at Berkeley, Berkeley, California

  • Steven G Louie

    University of California, Berkeley, Department of Physics, University of California, Berkeley, University of California at Berkeley and Lawrence Berkeley National Laboratory, UC Berkeley & Lawrence Berkeley National Laboratory, University of California at Berkeley, and Lawrence Berkeley National Laboratory, Lawrence Berkeley National Laboratory, Department of physics, University of California at Berkeley, Berkeley, California