| Abstract: | We employ state-of-the-art ab initio density functional theory techniques to investigatethe structural, dynamical, mechanical stability and electronic properties of the ternaryAgInS2 compoundsunder pressure. Using cohesive energy and enthalpy, we found that from the six potentialphases explored, the chalcopyrite and the orthorhombic structures were very competitive aszero pressure phases. A pressure-induced phase transition occurs around 1.78 GPa from the low pressure chalcopyritephase to a rhombohedral RH-AgInS2 phase. The pressure phase transition around 1.78 GPa isaccompanied by notable changes in the volume and bulk modulus. The calculations of thephonon dispersions and elastic constants at different pressures showed that thechalcopyrite and the orthorhombic structures remained stable at all the selected pressure(0, 1.78 and 2.5 GPa), where detailed calculations were performed, while the rhombohedralstructure is only stable from the transition pressure 1.78 GPa. Pressure effect on thebandgap is minimal due to the small range of pressure considered in this study. Themeta-GGA MBJ functional predicts bandgaps which are in good agreement with availableexperimental values. |
