Premium
First‐principles study of phonon‐mode softening under pressure: the case of GaN and AlN
Author(s) -
Wagner J.M.,
Bechstedt F.
Publication year - 2003
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/pssb.200301603
Subject(s) - softening , phonon , eigenvalues and eigenvectors , density functional theory , perturbation theory (quantum mechanics) , condensed matter physics , materials science , perturbation (astronomy) , mode (computer interface) , matrix (chemical analysis) , total energy , physics , quantum mechanics , composite material , computer science , operating system , psychology , displacement (psychology) , psychotherapist
The origin of the mode softening under pressure of the low‐frequency E 2 phonon of GaN and AlN is investigated by first‐principles density‐functional calculations. Using the eigenvectors of these modes as obtained from diagonalizing a dynamical matrix which is calculated using density‐functional perturbation theory, a frozen‐phonon calculation shows that the softening is mainly caused by an increased destabilization due to the Ewald energy, which is nearly counterbalanced by the other contributions to the total energy in the case of AlN, but only partially so for GaN.