Temperature variation of lattice parameter and optical energy gap values of the compounds CdIn2Te4 AND MnIn2Te4

X-Ray powder diffraction measurements, in the range from 300 K to 700 K, and optical absorption measurements, in the range 20-300 K, were made on polycrystalline samples of CdIn2Te4 and MnIn2Te4 compounds. In each case, from the analysis of the X-ray diffraction lines, accurate lattice parameter values were determined as a function of temperature, thus the thermal expansion coefficients of the materials are obtained. The absorption measurements were used to determine values of the optical energy gap E(g) as a function of temperature. The resulting curves of E(g) vs T were fitted to a simplified Manoogian-Leclerc equation and the fitted coefficients used to give values of (dE(g)/dT)(1) and (dE(g)/dT)(2) due to lattice dilation and electron-phonon contributions respectively. Hence, the deformation potentials of the valence and conduction bands were estimated for both compounds.