GW approach to degenerate systems

ORAL

Abstract

Many-body perturbation theory based on the GW approximation to the electron self energy describes accurately in first-principles calculations the electronic (quasiparticle) excited states of solids, clusters and molecules. However, despite the multitude of important systems with degenerate ground states, ranging from open-shell atoms and molecules to magnetic defects in solids, the GW approach has been applied almost exclusively to closed-shell systems. In this talk, we discuss some of the problems with existing GW calculations for degenerate systems, such as spin contamination, the multiplet problem, and the proper definition of the Green function in open-shell systems. Different formulations to overcome these problems are explored.

*This work was supported by National Science Foundation Grant No. DMR10-1006184, the U.S. Department of Energy 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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Authors

  • Johannes Lischner

    • UC Berkeley

  • Jack Deslippe

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

  • 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