Finite temperature quasiparticle self-consistent GW approximation

Technical Report · Sat Oct 01 00:00:00 EDT 2005

DOI:https://doi.org/10.2172/876339· OSTI ID:876339

Vanschilfgaarde, Mark ^[1]; Leonard, Fran­cois ^[1]; Desjarlais, Michael Paul ^[1]; Kotani, Takao ^[1]; Faleev, Sergey V ^[1]

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1. Sandia National Lab. (SNL-CA), Livermore, CA (United States)

We present a new ab initio method for electronic structure calculations of materials at finite temperature (FT) based on the all-electron quasiparticle self-consistent GW (QPscGW) approximation and Keldysh time-loop Green's function approach. We apply the method to Si, Ge, GaAs, InSb, and diamond and show that the band gaps of these materials universally decrease with temperature in contrast with the local density approximation (LDA) of density functional theory (DFT) where the band gaps universally increase. At temperatures of a few eV the difference between quasiparticle energies obtained in FT-QPscGW and FT-LDA approaches significantly reduces. This result suggests that existing simulations of very high temperature materials based on the FT-LDA are more justified then it might appear from well-known LDA band gap errors at zero-temperature.

• Research Organization: Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC04-94AL85000
• OSTI ID: 876339
• Report Number(s): SAND-2005-6347
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
DIAMONDS
ELECTRONIC STRUCTURE
SILICON
GERMANIUM
GALLIUM ARSENIDES
INDIUM ANTIMONIDES
ENERGY GAP
TEMPERATURE DEPENDENCE
DENSITY FUNCTIONAL METHOD
COMPUTERIZED SIMULATION
Plasma density
Materials-Optical properties
Materials-Compression testing