First-principles study on the structural, elastic and electronic properties of the four Si3Sb4 compounds

Abstract

For novel [Formula: see text]-Si3Sb4, pseudocubic-Si3Sb4, cubic-Si3Sb4 and [Formula: see text]-Si3Sb4, the structural, elastic and electronic properties are investigated using first-principles density functional theory (DFT). The elastic constants and phonon dispersion spectra show that they are mechanically and dynamically stable. The bulk moduli, shear moduli, Young’s moduli, Poisson’s ratios and Pugh ratios for the four compounds have been calculated. The bulk moduli indicate that the bond strength of [Formula: see text]-Si3Sb4 is stronger than others. The values of the Poisson’s ratios and Pugh ratios show that pseudocubic-Si3Sb4 is the stiffest among the four Si3Sb4 compounds. Tetragonal Si3Sb4 are more brittle than cubic Si3Sb4. For the four Si3Sb4 compounds, the elastic anisotropies are analyzed via the anisotropic indexes and the 3D surface constructions. The [Formula: see text]-Si3Sb4 elastic anisotropy is stronger than others and the [Formula: see text]-Si3Sb4 is weaker than others. The calculated band structures show that they exhibit metallic features. The results of their TDOS show that there are many similarities. The peaks of TDOS are derived from the contributions of Si “s”, Si “p”, Sb “s” and Sb “p” states.