Substrate Renormalization of Quasiparticle Band Gaps and Exciton Binding Energies in Quasi-2D Materials

ORAL

Abstract

Atomically thin quasi-two-dimensional (quasi-2D) materials, such as monolayer transition-metal dichalcogenides, display a much weaker electronic screening compared to their bulk counterparts as well as restricted geometry for the motion of the electrons. As a result, electron-electron and electron-hole interactions are enhanced. Owing to the atomic dimension of layer thickness, quasi-2D materials are sensitive to the screening environment produced by substrates, which allows one to dramatically tune their quasiparticle and optical properties. In this work, we extend a method recently developed in our group to incorporate substrate screening into the calculation of quasiparticle and optical properties of quasi-2D materials. We perform full-frequency ab initio GW and GW-Bethe Salpeter equation (GW-BSE) calculations to quantify the effect of the substrate on the electronic and optical gaps of quasi-2D systems. We find that a careful treatment of the dynamical effects of substrate polarizability is necessary to explain the effect of the renormalization on metallic substrates.

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Presenters

  • Chin Shen Ong

    Physics, Univ of California - Berkeley

Authors

  • Chin Shen Ong

    Physics, Univ of California - Berkeley

  • Felipe da Jornada

    Department of Physics, University of California at Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory, Physics, Univ of California - Berkeley, UC Berkeley and Lawrence Berkeley National Lab

  • Diana Qiu

    Physics, University of California, Berkeley, Physics, Univ of California - Berkeley, Lawrence Berkeley National Lab and University of California - Berkeley

  • Steven Louie

    Physics, University of California, Berkeley, University of California, Berkeley, Physics, Univ of California - Berkeley, Univ of California - Berkeley, Physics, UC Berkeley, Physics Department, UC Berkeley and Lawrence Berkeley National Lab, Department of Physics, University of California at Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory, Department of Physics, University of California, Berkeley, Physics Department, University of California Berkeley and Lawrence Berkeley National Lab, Department of physics, University of California - Berkeley, Lawrence Berkeley National Lab and University of California - Berkeley, Materials Sciences Division, Lawrence Berkeley National Laboratory & Department of Physics, University of California at Berkeley, UC Berkeley and Lawrence Berkeley National Lab, Physics, University of California - Berkeley