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Electronic and Phonon Deformation Potentials of GaN and AlN: Ab initio Calculations versus Experiment
Author(s) -
Wagner J.M.,
Bechstedt F.
Publication year - 2002
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/1521-3951(200212)234:3<965::aid-pssb965>3.0.co;2-p
Subject(s) - pseudopotential , phonon , wurtzite crystal structure , condensed matter physics , materials science , ab initio , deformation (meteorology) , plane wave , electronic structure , stiffness , density functional theory , stress (linguistics) , electronic band structure , computational chemistry , physics , chemistry , quantum mechanics , composite material , linguistics , philosophy , zinc , metallurgy
The structural, electronic, and lattice‐dynamical properties of homogeneously strained wurtzite GaN and AlN are studied ab initio using a pseudopotential‐plane‐wave method and a linear‐response approach to the density‐functional theory. The elastic properties are characterized by the stiffness constants. Electronic and phonon deformation potentials as well as biaxial stress coefficients are determined. Discrepancies between experimental and theoretical results for the stress coefficients are widely due to deviating parameters and an incorrect stress–strain relation. We show that the biaxial stress coefficient of the high‐frequency E 2 phonon and of the electronic band gaps should be smaller than they were commonly determined so far. We find that the quasicubic approximation is not valid for the electronic deformation potentials of GaN but is reasonable for those of AlN instead.