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