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Table 1 Left, LDA calculated bandgaps (LMTO [36], Spin–Orbit effects included) for Γ, X L points for GaAs and Ge Right, QSGW bandgaps for the same points in Ge and GaAs (eV, 0 K), compared with measured values at 0 K. The self-energy was scaled by a factor 0.8, as described in the text. Raw (unscaled) QSGW levels are slightly larger than experiment

From: On the Chemical Origin of the Gap Bowing in (GaAs)1−xGe2x Alloys: A Combined DFT–QSGW Study

  LDA BANDGAP (eV) QSGW BANDGAP (eV)
Γ L X Γ L X
QSGW Exp QSGW Exp QSGW Exp
GaAs (dir.) 0.23 0.75 1.43 1.47 1.52a 1.73 1.80a 1.84 1.98a
Ge (indir) −0.22 −0.04 0.55 0.94 0.90b 0.74 0.74b 1.06 1.09b
  1. a Inferred from ellipsometry data in Ref. [45], using the QSGW Γ-X dispersion in the valence band (−3.37 eV)
  2. b Inferred from ellipsometry data in Ref. [46], using the QSGW Γ-X dispersion in the valence band (−3.98 eV)