Первопринципное исследование электронных, колебательных и упругих свойств кристаллов LiInTe-=SUB=-2-=/SUB=- и LiTlTe-=SUB=-2-=/SUB=-

Abstract

Using the sublattice method and density functional theory, the electronic struc-ture of a LiTlTe2 crystal with the chalcopyrite structure was studied for the first time and the equilibrium parameters of the crystal lattice a=6.7526 Å, c=13.3037 Å, u(Te)=0.2423 were calculated. It has been established that the valence bands of the LiTlTe2 crystal and its closest analogue LiInTe2 actually coincide in topol-ogy, and the LiTlTe2 crystal is a direct-gap semiconductor with a band gap of 0.63 eV and a crystal splitting of 0.04 eV. The partial contributions of the densi-ty of states are analyzed and the features of the formation of the valence and conduction bands of LiInTe2 and LiTlTe2 crystals due to the contributions of their sublattices are revealed: the structure of the valence bands of both crystals is completely determined by the interaction in the cationic tetrahedra of InTe4 and TlTe4. The vibrational modes and elastic constants are calculated, confirm-ing the stability and mechanical stability of the LiTlTe2 crystal.