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.

*This work is supported by NSF Grant DMR-1508412, DOE under Contract DE-AC02-05CH11231. Computational resources are provided by DOE at Lawrence Berkeley National Laboratory's NERSC facility.

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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