Substrate Renormalization of Quasiparticle Band Gaps, Exciton Binding Energies and Transport Properties of Quasi-2D Materials

ORAL

Abstract

Electrons in atomically thin quasi-2D materials, such as monolayer transition-metal dichalcogenides, are spatially confined in the out-of-plane direction and are also more weakly and differently screened than in bulk materials. Consequently, electron-electron and electron-hole interactions in quasi-2D materials are stronger and different compared to the bulk. Similarly, owing to the atomic dimension of layer thickness, quasi-2D materials are sensitive to screening environment produced by substrates, allowing one to dramatically tune their quasiparticle and optical properties. Here, we discuss 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 ab initio GW and GW-Bethe Salpeter equation (GW-BSE) calculations to quantify this effect on electronic and optical gaps of these systems. We will also discuss a theoretical upper bound of the screening effect. Lastly, we will show how substrate screening can be used to engineer a lateral heterojunction within homogeneous MoS2 monolayer.

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Presenters

  • Chin Shen Ong

    Physics, University of California at Berkeley

Authors

  • Chin Shen Ong

    Physics, University of California at Berkeley

  • Felipe Da Jornada

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

  • Diana Qiu

    Physics, University of California at Berkeley, Physics, University of California, Berkeley, Lawrence Berkeley National Lab and University of California, Berkeley, University of California - Berkeley, Lawrence Berkeley National Laboratory

  • Steven G. Louie

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