The effect of semicore electrons on the polarizability and band gaps in \textit{ab initio }planewave-pseudopotential (PW-PP) GW calculations

ORAL

Abstract

Understanding the effect of semicore electrons on \textit{ab initiio }PW-PP GW calculations is currently of great interest due to the increasing importance of complex materials with active semicore electrons, e.g.,the transition metal dichalcogenides. While past research has found a significant effect due to the inclusion of semicore electrons, it did not fully explore the nature of the various deviations of traditional valence-only PW-PP GW calculations from calculations that include the semicore electrons. We study this issue in the simple system of the Si atom, where the effect is more easily isolated, and then extend our results to bulk Si, and other bulk systems. We present results showing the effect of semicore electrons on various contributions to the GW self energy, and discuss the nature of differences with the traditional PW-PP approach. We present methods to efficiently include the effect of semicore electrons in a hierarchy of computational cost and accuracy.

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Authors

  • Derek Vigil-Fowler

    University of California - Berkeley, Lawrence Berkeley National Laboratory

  • Brad Malone

    School of Engineering and Applied Sciences, Harvard University, Harvard University

  • Steven.G. Louie

    Department of Physics, University of California at Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory, UC Berkeley physics/ LBNL MSD, Dept. of Physics UC Berkeley and Lawrence Berkeley National Lab, University of California - Berkeley, Lawrence Berkeley National Laboratory, Physics Department, UC Berkeley and Lawrence Berkeley National Lab, University of California at Berkeley, University of California, Berkeley, UC Berkeley and Lawrence Berkeley National Laboratory, Univ of California - Berkeley, Dept. of Physics, University of California, Berkeley and Materials Science Division, Lawrence Berkeley National Laboratory