First-principles study of the electronic, optical, and lattice dynamics properties of LiInSe2 polymorph

First-principles calculations of the electronic, optical, and lattice dynamics properties of LiInSe2 polymorph were performed with the density functional theory plane-wave pseudopotential method. The results of electronic structure reveal that the different coordinated structure for alpha-NaFeO2-type LiInSe2 leads to the broadening of density of states and the smaller band gap. Various optical properties, including the dielectric function, reflectivity, absorption coefficient, refractive index, and the energy-loss spectrum as functions of the photon energy were calculated and are found to be in good agreement with experiments. We also presented phonon dispersion relation, zone-center optical mode frequency, density of phonon states, and some thermodynamic properties, such as constant volume heat capacity and Debye temperature. The results show that the alpha-NaFeO2-type LiInSe2 does not only have special optical properties but also demonstrates special vibrational properties and thermodynamic properties, which may lead to significance research meaning and application value.