Ab initio and experimental study of electronic, optical, and vibrational properties of CdGa$_{2}$Te$_{4}$

The electronic, optical, and lattice vibrational properties of CdGa$_2$Te$_4$ were studied experimentally using spectral ellipsometry, Raman scattering (Raman scattering) and infrared (IR) spectroscopy, as well as theoretically using the density functional theory (DFT). Eight Raman-active modes and twelve IR-active modes were detected and identified from consideration of the point group symmetry. Based on the analysis of the electronic spectrum and the density of states, the nature of the chemical bond in this semiconductor compound is determined. The theoretically calculated results are compared with the experimental data of the present work and with the results of experimental data available in the literature obtained by infrared spectroscopy and Raman scattering.