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The Dynamical Electron–Phonon Mode Coupling in Jahn‐Teller Crystals with Antiferroelastic Ordering
Author(s) -
Kaplan M. D.
Publication year - 1983
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.2221180110
Subject(s) - soft modes , condensed matter physics , jahn–teller effect , phonon , coupling (piping) , mode (computer interface) , mode coupling , electron , physics , acoustic dispersion , dispersion (optics) , ferroelectricity , phase (matter) , dielectric , materials science , quantum mechanics , ion , computer science , metallurgy , operating system
The dispersion equation for the coupled electron‐phonon modes, active in the antiferrodistortion ferroelectric phase transition, is obtained by the Green function method. It is shown, that in this case the odd (at T > T c ) quasielectronic branch is the soft mode, which gives a principal contribution to the dielectric anomalies of the crystal. The acoustic property anomalies of the system are due to the interaction of the acoustic mode with the even electronic mode, which is also soft, but is non‐vanishing at T = T c . The characteristics of the dynamical coupling of the odd electronic mode with the acoustic mode are discussed in the long wave approximation.