Open AccessPhonon dispersion calculations using the Vaks model in antiferroelectric lead zirconate
Author(s) -
Daria Andronikova,
R. G. Burkovsky,
A. V. Filimonov,
A. K. Tagantsev,
S. B. Vakhrushev
Publication year - 2015
Publication title -
journal of advanced dielectrics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.38
H-Index - 13
eISSN - 2010-135X
pISSN - 2010-1368
DOI - 10.1142/s2010135x15500162
Subject(s) - phonon , zirconate , condensed matter physics , antiferroelectricity , dispersion relation , dispersion (optics) , wave vector , lattice (music) , phase transition , instability , materials science , soft modes , physics , dielectric , ferroelectricity , optics , mechanics , quantum mechanics , ceramic , acoustics , composite material , titanate
The calculations of low-energy phonon dispersion relations in lead zirconate (PZ) have been carried out using the Vaks model. This model takes into account only five low-energy phonon modes and their interactions. It has been shown that this model allows to achieve good agreement not only between calculated and experimental transverse acoustic phonon dispersion but also between their temperature dependences. It has been shown 5-mode system, which describes low-energy phonon dispersion in PZ, is close to unstable state. Even a little change of interaction parameter can lead to lattice instability with nonzero wave vector q crit . Wave vector q crit could have any value, including irrational one. In this case, system will undergo an incommensurate phase transition.