Electronic, mechanical, dielectric and optical properties of cubic and orthorhombic tin monosulfide

Electronic, mechanical, dielectric and optical properties of tin monosulfide (SnS) are studied by means of first principles calculations. Theoretical calculations based on density functional theory are performed for two (cubic and orthorhombic) crystalline phases of SnS. Calculated structural and mechanical properties of cubic (pi-phase) and orthorhombic SnS fulfil the structural and mechanical stability criteria. The calculated mechanical properties show anisotropic behavior of both phases. Density of states (DOS) spectra reveal that the cubic pi-SnS phase exhibit 1.40% spin-polarization, while orthorhombic SnS does not show spin polarization. Band structure calculations reveal that the cubic pi-phase has direct band gap (E-g = 1.279 eV), while orthorhombic phase exhibits indirect band gap (E-g = 1.149 eV). Electronic calculations show pi-type semiconducting nature of cubic and orthorhombic SnS. Dielectric behavior of cubic and orthorhombic SnS shows direct and indirect optical transition, respectively. The calculated optical parameters show isotropic behavior of cubic pi-SnS, whereas the orthorhombic SnS exhibits anisotropic optical behavior. Based on these theoretical results, it is suggested that the properties of tin monosulfide can be tailored if structural phase is controlled during material's synthesis.