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Temperature dependence of Raman-active mode frequencies and linewidths in TlGaSe2 layered crystals

Raman spectra of TlGaSe2 crystal at different temperatures are discussed. The temperature dependence of frequency shifts and linewidths of the Raman peaks in the frequency region of 10-320 cm(-1) have been measured in the range from 50 to 320 K. The analysis of the experimental data showed that the temperature dependencies of phonon frequencies and linewidths are well described by considering the contributions from thermal expansion and lattice anharmonicity. The anharmonic contribution (phonon-phonon coupling) is found to be due to three-phonon processes. (c) 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.