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Dielectric function of antiferroelectric thin films
Author(s) -
Wesselinowa J. M.
Publication year - 2005
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.200440025
Subject(s) - antiferroelectricity , dielectric , thin film , dielectric function , condensed matter physics , function (biology) , transverse plane , materials science , random phase approximation , phase (matter) , dielectric response , physics , nanotechnology , optoelectronics , ferroelectricity , quantum mechanics , structural engineering , evolutionary biology , biology , engineering
A Green's function technique is developed to study the real and imaginary parts of the dielectric function ε ( k , E ) for antiferroelectric thin films below and above T c . We calculate the two‐particle Green's function 〈〈 S z ( k ‖ ) S z (– k ‖ )〉〉 beyond the random phase approximation taking into account the coupling between the transverse and the longitudinal relaxing mode. The dependence on temperature and film thickness is discussed and compared with the experimental data. Due to stronger damping effects in thin films the peak of the dielectric function becomes broader with decreasing film thickness. The temperature, where the dielectric function offers a maximum, can decrease or increase in dependence on the strength of the exchange interaction parameter. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)