Effects of screening from electron-hole interactions on quasiparticle excitations within the <i>GW</i> approach

ORAL

Abstract

For first-principles excited-state calculations, there exist in the literature various schemes to do “self-consistent” GW calculations at different levels going beyond the one-shot G0W0 approach. For single-particle excitations (e.g., the quasiparticle bandgap in semiconductors), a straightforward self-consistent update of both the single-particle Green’s function G and the screened Coulomb interaction W within the random-phase approximation (RPA) for the self-energy generally gives less satisfactory results than those from the G0W0 approach as compared to experiments. This is because the dielectric screening is underestimated within RPA using quasiparticle energies and the error will be accumulated, since electron-hole interactions (excitonic effects) are neglected in the RPA polarizability. In this work, we investigate the importance of electron-hole interactions in modifying W in the GW self-energy. The theoretical formalism is presented, along with first-principles results for various semiconductors.

*This work was supported by the Theory of Materials Program and C2SEPEM at LBNL which are funded by the U.S. DOE under Contract No. DE-AC02-05CH11231, and by the National Science Foundation. Computational resources have been provided by NERSC and XSEDE.

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Presenters

  • Meng Wu

    • University of California at Berkeley and Lawrence Berkeley National Laboratory
    • University of California, Berkeley

Authors

  • Meng Wu

    • University of California at Berkeley and Lawrence Berkeley National Laboratory
    • University of California, Berkeley

  • Zhenglu Li

    • Department of Physics, University of California, Berkeley
    • UC Berkeley & Lawrence Berkeley National Laboratory
    • University of California at Berkeley, and Lawrence Berkeley National Laboratory
    • University of California at Berkeley and Lawrence Berkeley National Laboratory
    • Lawrence Berkeley National Laboratory
    • University of California, Berkeley
    • Lawrence Berkeley National Laboratory and University of California at Berkeley
    • Department of physics, University of California at Berkeley, Berkeley, California

  • Steven G Louie

    • University of California, Berkeley
    • Department of Physics, University of California, Berkeley
    • University of California at Berkeley and Lawrence Berkeley National Laboratory
    • UC Berkeley & Lawrence Berkeley National Laboratory
    • University of California at Berkeley, and Lawrence Berkeley National Laboratory
    • Lawrence Berkeley National Laboratory
    • Department of physics, University of California at Berkeley, Berkeley, California