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Title:First-principles calculations of the mechanical and structural properties of GaNxAs1−x: Lattice and elastic constant
Authors:G. Stenuit, S. Fahy, 2007
Abstract: Using first-principles total energy calculations, we have investigated the lattice and elastic constants in GaNxAs1−x alloys as functions of the nitrogen concentration x. Ab initio density functional theory is used to find the relaxed atomic configurations and elastic constants for substitutional nitrogen in supercells containing up to 128 atoms. The effect of N2 and NAs split interstitial substitutions (ISs) on the mechanical properties has also been calculated in cells up to 64 atoms. Atomic positions and geometries in all supercells have been relaxed, and the elastic constant tensors for simple cubic 8-atom supercells have been computed. Deviation of the lattice constants from Vegard’s law due to IS is shown to be substantial. We provide analytical expressions for the concentration dependence of the lattice and elastic constants in GaNxAs1−x alloys, including normal and split-interstitial substitutions, and find the ratio rb of the bowing coefficients of the elastic constants C11 and C12.
ICHEC Project:Electronic transport and vibrational properties in dilute GaAs:N
Publication:Phys. Rev. B 76 (2007) 035201
URL: http://journals.aps.org/prb/abstract/10.1103/PhysRevB.76.035201
Status: Submitted

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