Anharmonic line shift and linewidth of the Raman modes in TlInS₂ layered crystals

Abstract

The temperature dependence of the unpolarized Raman spectra from TlInS 2 layered crystal was measured between 10 and 300 K. The analysis of the experimental data showed that the temperature dependences of wavenumbers and linewidths are well described by considering the contributions from thermal expansion and lattice anharmonicity. The purely anharmonic contribution (phonon-phonon coupling) was found to be due to three-phonon processes. This work demonstrates that the two Raman modes at 280.9 and 292.3 cm −1 exhibit changes toward high wavenumbers as the temperature is raised from 10 to 300 K.

Anharmonicity Effects in Nanocrystals Studied by Raman Scattering Spectroscopy

“…The Raman spectra of various amorphous or crystalline materials show changes in line position and bandwidth with temperature [1][2][3][4]. This changes manifest in shift of line position and a change in line width and intensity.…”

Vibrational and structural properties in the dihydrate sodium tungstate and in the dihydrate sodium molybdate crystals

“…4 shows that the temperature dependence in the Raman modes can be better followed through the wavenumbers vs. temperature plots. In a low temperature range (13-300 K), the wavenumbers vs. temperature fittings, were better reached by using the expected dependence due to anharmonic phonon decay as follows [17][18][19][20]:…”

Temperature Dependence of Raman-Active Modes of TlIn(0.95Se0.05)2 Single Crystals

“…Several works were devoted to Raman spectroscopic studies of TlIn(S 1− Se ) 2 solid solutions (0 < < 1), where the compositional transformation of Raman spectra was investigated mostly at room temperature [15][16][17][18][19], as well as at lower temperatures [19]. With regard to the studies of vibrational spectra in a broad temperature range, including the phase transition range, such data were obtained for TlInS 2 crystals by several research teams [20][21][22][23][24][25][26][27][28][29]. A detailed analysis of the polarized Raman spectra of TlInS 2 was performed in a broad temperature range, including the temperature dependences of spectral positions and half-widths of low-frequency modes, and a conclusion was made on the existence of soft modes [24,25].…”

“…A detailed analysis of the polarized Raman spectra of TlInS 2 was performed in a broad temperature range, including the temperature dependences of spectral positions and half-widths of low-frequency modes, and a conclusion was made on the existence of soft modes [24,25]. Recently, several studies were published including the temperature-dependent analysis of the spectral positions and half-widths of other Raman modes in the TlInS 2 crystal spectra [26][27][28][29]. A detailed analysis of the spectral interval 120-400 cm −1 in the temperature interval 77-300 K is presented in Ref.…”