Optical absorption study by ab initio downfolding approach: Application to GaAs

Kazuma Nakamura, Yoshihide Yoshimoto, Ryotaro Arita, Shinji Tsuneyuki, Masatoshi Imada

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

We examine whether the essence and quantitative aspects of electronic excitation spectra are correctly captured by an effective low-energy model constructed from an ab initio downfolding scheme. A global electronic structure is first calculated by ab initio density-functional calculations with the generalized gradient approximation. With the help of constrained density-functional theory, the low-energy effective Hamiltonian for bands near the Fermi level is constructed by the downfolding procedure in the basis of maximally localized Wannier functions. The excited states of this low-energy effective Hamiltonian ascribed to an extended Hubbard model are calculated by using a low-energy solver. As the solver, we employ the Hartree-Fock approximation supplemented by the single-excitation configuration-interaction method considering electron-hole interactions. The present three-stage method is applied to GaAs, where eight bands are retained in the effective model after the downfolding. The resulting spectra well reproduce the experimental results, which indicate that our downfolding scheme offers a satisfactory framework of the electronic-structure calculation, particularly for the excitations and dynamics as well as for the ground state.

Original languageEnglish
Article number195126
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume77
Issue number19
DOIs
Publication statusPublished - 2008 May 29
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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