LOW-TEMPERATURE PHASE-TRANSITIONS IN TLGAS2 LAYER CRYSTALS

Download

index.pdf

Date

1993-11-01

Author

AYDINLI, A
ELLIALTIOGLU, R
ALLAKHVERDIEV, KR
ELLIALTIOGLU, S
Hasanlı, Nızamı

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

100
views

0
downloads

Polarized Raman scattering spectra of TlGaS2 layer crystals have been studied for the first time as a function of temperature between 8.5 and 295 K. No evidence for a soft mode behaviour has been found. The anomalies observed in the temperature dependence of low- and high-frequency phonon modes at approximately 250 and approximately 180 K, respectively, are explained as due to the phase transitions. It is supposed that the phase transitions are caused by the deformation of structural complexes GaS4, rather than by slippage of Tl atom channels in [110] and [110BAR] directions, which is mainly responsible for the appearance of the low-temperature ferroelectric phase transitions in other representatives of TlBX2 layer compounds.

Subject Keywords

Raman, Tigase2, Spectra, Tlins2, Soft

URI

https://hdl.handle.net/11511/46664

Journal

SOLID STATE COMMUNICATIONS

DOI

https://doi.org/10.1016/0038-1098(93)90230-k

Collections

Department of Physics, Article

Suggestions

OpenMETU
Core

Temperature dependence of Raman-active mode frequencies and linewidths in TlGaSe2 layered crystals Yuksek, NS; Hasanlı, Nızamı (2005-03-01) 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 coupl...
Low-temperature visible photolummescence and optical absorption in Tl2In2Se3S semiconductor Güler, Işıkhan; Hasanlı, Nızamı; Turan, Raşit (2007-05-31) The emission band spectra of undoped T1(2)In(2)Se(3)S layered crystals have been studied in the temperature range of 25-63 K and the wavelength region of 570-700nm. A broad photoluminescence band centered at 633 nm (1.96 eV) was observed at T = 25 K. Variation of emission band has been studied as a function of excitation laser intensity in the 2.7-111.4mWcm(-2) range. Radiative transitions from shallow donor level located at 0.03 eV below the bottom of conduction band to deep acceptor level located at 0.23 ...
Low-Temperature Thermo luminescence Studies on TlInS2 Layered Single Crystals Isik, M.; Delice, S.; Hasanlı, Nızamı (2014-12-01) Thermoluminescence characteristics of TlInS2 layered single crystals grown by the Bridgman method were investigated in the low temperature range of 10-300 K. The illuminated sample with blue light (approximate to 470 nm) at 10 K was heated at constant heating rate. Curve fitting, initial rise and various heating rate methods were used to determine the activation energy of the trap levels. All applied methods showed good consistency about the presence of five trapping centers located at 14, 19, 350, 420, and...
Alpha - beta transition in quartz Lider, Mustafa Cem; Yurtseven, Hasan Hamit; Department of Physics (2011) Alpha-Beta transition in quartz is studied using the Raman scattering. The Raman frequencies of some lattice modes are analyzed at various temperatures close to the alpha beta transition in quartz. For this analysis, the experimental data from the literature is used and the soft mode behavior of those Raman phonons is investigated . On the basis of the predictions of some models, the temperature dependencies for the Raman frequencies of the lattice modes which move towards zero (soft mode) and their bandwid...
Low-temperature absorption edge and photoluminescence in layered structured Tl2Ga2S3Se single crystals Hasanlı, Nızamı (2012-11-01) The absorption edge of undoped Tl2Ga2S3Se crystals have been studied through transmission and reflection measurements in the wavelength range 440-1100 nm and in the temperature range 10-300 K. The absorption edge was observed to shift toward lower energy values with increasing temperature. As a result, the rate of the indirect band gap variation with temperature gamma = -2.6 x 10(-4) eV/K and the absolute zero value of the band gap energy E-gi(0)=2.42 eV were obtained.

Citation Formats

A. AYDINLI, R. ELLIALTIOGLU, K. ALLAKHVERDIEV, S. ELLIALTIOGLU, and N. Hasanlı, “LOW-TEMPERATURE PHASE-TRANSITIONS IN TLGAS2 LAYER CRYSTALS,” SOLID STATE COMMUNICATIONS, pp. 387–390, 1993, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/46664.