Constructing unoccupied states for G$_0$W$_0$ quasiparticle calculations from plane-waves

ORAL

Abstract

Standard methods of first-principles calculations of the quasiparticle energies within the G$_0$W$_0$ scheme require summing over large numbers of unoccupied states. The generation of these states within the ab initio pseudopotential plane-wave density functional theory (DFT) quickly becomes a bottleneck of the calculation with increasing system size, especially in low-dimensional systems. In this work, we propose a method for approximating the high-energy continuum and resonant states in low-dimensional systems. The continuum and resonant states above a chosen energy are replaced with symmetrized plane-waves and localized DFT states computed with short-range localized basis functions (such as in the SIESTA code), respectively. The Gram-Schmidt process is used to orthogonalize these constructed high-energy unoccupied states. The method opens a route towards precise G$_0$W$_0$ quasiparticle calculations in large low-dimensional systems using a small number of unoccupied DFT states. This work was supported by NSF Grant No. DMR10-1006184, the U.S. DOE under Contract No. DE-AC02-05CH11231. Computational resources have been provided by NSF through TeraGrid at NICS and DOE at LBNL's NERSC.

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Authors

  • Georgy Samsonidze

    • University of California at Berkeley and Lawrence Berkeley National Lab

  • Manish Jain

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

  • Jack Deslippe

    • University of California-Berkeley and Lawrence Berkeley National Lab
    • UC Berkeley

  • Marvin L. Cohen

    • University of California at Berkeley and Lawrence Berkeley National Laboratory
    • University of California, Berkeley
    • University of California Berkeley
    • University of California at Berkeley and Lawrence Berkeley National Lab
    • Department of Physics, University of California, Berkeley, and Materials Science Division, Lawrence Berkeley National Laboratory

  • Steven G. Louie

    • University of California, Berkeley and Lawrence Berkeley National Laboratory
    • Department of Physics, University of California at Berkeley, and Materials Sciences Division, Lawrence Berkeley National Lab
    • UC Berkeley
    • Department of Physics, U. C. Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory
    • University of California at Berkeley and Lawrence Berkeley National Laboratory
    • University of California-Berkeley and Lawrence Berkeley National Lab
    • Department of Physics, University of California at Berkeley
    • Phys Dept. UC Berkeley
    • Department of Physics, University of California, Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
    • University of California at Berkeley and Lawrence Berkeley National Lab