Ab initio calculations of phonon dispersion and lattice dynamics in TlGaTe₂

Abstract

This work reports the results of DFT‐based calculations of phonon spectra of TlGaTe2. The dispersion of phonon bands was calculated along the directions of Brillouin zone (BZ) that include symmetry points. The calculated phonon frequencies at the centre of BZ were compared with those obtained by Raman spectroscopy with the aid of a confocal laser microscopy system. A fairly good agreement between the calculated and experimental data was found. Complimentary, molar heat capacity at constant volume and Debye temperature were calculated in the range 5÷500 K on the base of the obtained phonon density of states. The obtained temperature dependencies were compared with available experimental data.The results of comparison were satisfactory. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

First-Principle Calculation of High Absorption-TlGaTe2 for Photovoltaic Application

“…In Table 2, we presented our calculated values for R-active and IR-active modes along with results published earlier in [31] and the experimental values [9]. Note that our calculated R-active and IR-active modes are in better agreement with the experimental results obtained in [9] than [31]. However, the calculated phonon frequencies of TlGaTe 2 are lower than the corresponding experimental phonon frequencies.…”

“…Our calculated IR-active modes confirm the existence of two A 2u mode with frequencies of 1 A 2u = 18 (27 cm −1 [9]) and 2 A 2u = 170 (175 cm −1 [9]), along with three E u mode with frequencies of 1 E u = 34 (44 cm −1 [9]), 2 E u = 78(88 cm −1 [9]) and 3 E u = 188(192 cm −1 [9]). In Table 2, we presented our calculated values for R-active and IR-active modes along with results published earlier in [31] and the experimental values [9]. Note that our calculated R-active and IR-active modes are in better agreement with the experimental results obtained in [9] than [31].…”

“…As seen in Figure 3a and Table 2, we observed seven R-active modes in the Raman spectra for TlGaTe 2 , whereas Gasanly et al [9] found only three out of seven predicated R-active modes. Our calculated R-active modes confirm the existence of three E g mode with frequencies of 1 E g = 19 cm −1 (16 cm −1 [31]), 2 E g = 60 cm −1 (67 cm −1 [9]) and 3 E g = 157 cm −1 (165 cm −1 [9]). Our calculated R-active modes confirm the existence of one A 1g mode with a frequency of A 1g = 128 cm −1 (135 cm −1 [9]) and three B 1g mode with frequencies of B 1g = 76 cm −1 (76 cm −1 [31]), B 1g = 99 cm −1 (99 cm −1 [31]) and 2 B 2g = 216 cm −1 (210 cm −1 [31]).…”

Фотоиндуцированная обратимая локальная деформация рельефа поверхности в объемных монокристаллах TlInSe-=SUB=-2-=/SUB=-, TlGaTe-=SUB=-2-=/SUB=- и TlSe

“…Локализованное фотоиндуцированное изменение размеров наблю-далось нами в полупроводниковых монокристаллах TlInSe 2 и других материалах семейства TlMeX 2 (Me = In, Ga, Tl; X = Se, S, Te) [6,7], которые являются центросимметричными при комнатной температу-ре [8,9]. Будучи обратимым при облучении прерывающимся светом, это локализованное расширение вокруг области облученного лазерного пятна является наиболее отличительной особенностью соединений TlMeX 2 с перспективой использования в различных механических приводах, управляемых светом.…”