Ab initio density functional theory investigation of the structural, electronic and optical properties of Ca3Sb2 in hexagonal and cubic phases

•Physical properties of Ca3Sb2 in hexagonal and cubic phases are investigated.•It is found that the hexagonal phase is an indirect gap semiconductor.•Ca3Sb2 is a direct-gap semiconductor at the Γ point in the cubic phase.•By increasing pressure the semiconducting band gap and anti-symmetry gap are decreased.

A density functional theory study of structural, electronical and optical properties of Ca3Sb2 compound in hexagonal and cubic phases is presented. In the exchange–correlation potential, generalized gradient approximation (PBE-GGA) has been used to calculate lattice parameters, bulk modulus, cohesive energy, dielectric function and energy loss spectra. The electronic band structure of this compound has been calculated using the above two approximations as well as another form of PBE-GGA, proposed by Engle and Vosko (EV-GGA). It is found that the hexagonal phase of Ca3Sb2 has an indirect gap in the Γ→N direction; while in the cubic phase there is a direct-gap at the Γ point in the PBE-GGA and EV-GGA. Effects of applying pressure on the band structure of the system studied and optical properties of these systems were calculated.

Graphical abstractA density functional theory study of structural, electronic and optical properties of Ca3Sb2 compound in hexagonal and cubic phases is presented.Figure optionsDownload full-size imageDownload as PowerPoint slide