Electronic Structure of AlP Under Pressure Using Semiempirical Method

Abstract

The effect of pressure on the structural and electronic parameters of zinc-blende aluminum phosphide crystal has been investigated using the large unit cell within the framework of complete neglect of differential overlap and the linear combination of atomic orbital approximation. Cohesive energy, indirect band gap, valence bandwidth, conduction bandwidth, bulk modulus, and valence charge distribution are all obtained. The calculations show a good agreement of lattice constant, cohesive energy, valence bandwidth, and bulk modulus with the experimental data. The calculated band gap is twice the experimental value. This high value of the band gap is expected in Hartree-Fock method. The effect of pressure on the aforementioned properties is investigated. It is found that the indirect band gap, valence bandwidth, bulk modulus and cohesive energy increase with increasing pressure, while the conduction bandwidth decreases. The maximum value of pressure is taken to be 9 GPa, because beyond this value, the phase of AlP transforms from zinc blende phase to nickel arsenic phase. PACS: 71.10-w, 71.15-m, 71.15. Ap, 71.15. Nc, 64.10.+h.