Far-infrared study and lattice dynamics simulation of Cs₂HgBr₄ crystal

Abstract

Far-infrared reflectivity investigations of Cs₂HgBr₄ crystal were performed in the temperature region of 10-297 K. A sequence of the phase transitions can be recognised by activation of new modes below the phase transition points. In order to interpret the experimental IR data at room temperature the lattice-dynamical modelling in the framework of atomic model was carried out. Comparison of the calculated phonon frequencies with the experimental ones shows a reasonable agreement for most of them. The eigenvector analysis is presented.

Key Words:

• lattice dynamics
• phonon
• infrared and Raman spectra