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Phonon energy renormalization in KDP‐type ferroelectrics
Author(s) -
Wesselinowa J. M.,
Apostolov A. T.,
Filipova A.
Publication year - 1996
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.2221970226
Subject(s) - anharmonicity , phonon , condensed matter physics , renormalization , physics , ising model , renormalization group , quantum mechanics
A Green's function technique is used to study the influence of spin‐phonon interactions in the Ising model with a transverse field including higher‐order anharmonic terms. The renormalized phonon energy has been evaluated for the first time beyond the RPA. At low temperatures both, the anharmonic spin‐phonon and phonon‐phonon interactions including cubic and quadratic terms play an important role, whereas near and above the Curie temperature only the anharmonic phonon‐phonon interaction contributes to the renormalization of the phonon energy.