Study of phase transitions and lattice dynamics, elastic and electronic properties, bonding and weak interactions analysis of YCuS2 in P212121, [formula omitted] and [formula omitted] space group structures

Abstract

The present work shows several physical behaviors of YCuS2 that are still unknown, such as electronic properties, phase transitions, mechanical properties and several dynamical behaviors. This study has shown that YCuS2 is elastically stable in the three studied structures (P212121, P-421m and I-42d), while it is dynamically stable in P212121 structure only, which shows that this latter is that of the ground state and the rest (P-421m and I-42d) are those of phase transitions. For P212121 structure, the found lattice parameters are very close to those of experimental and theoretical ones. Electronic properties have shown that YCuS2 is a semiconductor in all three studied structures with a slightly wider band-gap for P212121 structure. These results highlight the optoelectronic importance of this compound. The dynamical study of YCuS2 has been carried out taking into consideration the LO/TO splitting. The zone-center modes have been presented. Bonding analysis using QTAIM has shown the presence of an intermediate bonding type between the different atoms, while the different weak interactions have been identified and located by NCI method.