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.

*This work was supported by NSF Grant No. DMR-1508412 and the DOE under Contract No. DE-AC02-05CH11231. Computational resources have been provided by DOE at Lawrence Berkeley National Laboratory's NERSC facility.

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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