STRUCTURAL AND ELECTRONIC-PROPERTIES OF INSB UNDER PRESSURE

We have investigated the structural and electronic properties of the III-V semiconductor InSb under pressure by means of first-principles density-functional total-energy calculation using the all-electron full potential linear augmented plane-wave method. We find that in the high-pressure region, the beta-Sn structure is unstable and a body-centered orthorhombic structure (space group Imm2) is energetically more favorable. Calculated structural parameters (a/b and a/c ratios, and atomic positions) are in good agreement with a recent highly accurate x-ray-diffraction experiment using an image plate area detector. Theoretical lattice constant and bulk modulus for the normal-pressure zincblende structure is also in very good agreement with experiments. We present calculated structural properties as well as band structures and charge densities for the various structures studied. We discuss the processes of the phase transformation, and also the bonding and structural stabilities in terms of the calculated electronic properties.