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.

**This work was supported by the Theory of Materials Program at the Lawrence Berkeley National Laboratory funded by the U.S. Department of Energy, Office of Basic Energy Sciences under Contract No. DE-AC02-05CH11231, and by the National Science Foundation. Computational resources were provided by NERSC and XSEDE.

–

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