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Substrate-Induced Dynamical Anti-Screening of Excitons in Quasi-2D Materials: Renormalization of Quasiparticle and Optical Excitations

ORAL

Abstract

It is now well established that screening from substrates can strongly reduce the many-electron interactions in quasi-2D insulating materials, and renormalize both the quasiparticle bandgap and exciton binding energy in such systems. However, for metallic substrates, the frequency dependence of screening plays a paramount role that is often ignored. Here, we show that the frequency dependence of metallic substrate screening can induce a strong anti-screening effect in the quasi-2D insulator and lead to anomalously non-hydrogenic exciton energy levels, i.e., there are dramatic additional changes that go beyond the q-dependent static screening of quasi-2D materials. A systematic first-principles study of renormalizations by a wide range of experimentally motivated substrates is carried out, and our calculated results provide conceptual and quantitative explanation of experiments.

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Presenters

  • Chin Shen Ong

    University of California, Berkeley

Authors

  • Chin Shen Ong

    University of California, Berkeley

  • Felipe H. da Jornada

    Physics, Unviersyt of Calfornia, Berkeley, Materials Science, Stanford University, University of California, Berkeley

  • Diana Qiu

    Department of Mechanical Engineering and Materials Science, Yale University, Physics, Unviersyt of Calfornia, Berkeley, Yale University, Mechanical Engineering and Materials Science, Yale University, University of California, Berkeley

  • Steven Louie

    University of California at Berkeley, and Lawrence Berkeley National Laboratory, Department of Physics, University of California, Berkeley, Berkeley, California 94720, USA and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, C, University of California, Berkeley, Department of Physics, University of California, Berkeley, Lawrence Berkeley National Laboratory and University of California at Berkeley, Department of Physics, University of California at Berkeley and Lawrence Berkeley National Laboratory, Department of Physics, UC Berkeley, Physics, Unviersyt of Calfornia, Berkeley, Physics, University of California, Berkeley, Physics, University of California, Berkeley and Lawrence Berkeley National Lab