Electronic structure calculations of PbTe

The full potential linearized augmented plane wave (LAPW) method was applied to study the electronic structure of the PbTe compound. Calculations of the band structure, density of states, strain energy and total energy as a function of lattice constant have been performed in the B1(NaCl) and B2(CsCl) structures. The equilibrium lattice constant, the band gap, the pressure variation of the energy gap, the bulk moduli and the elastic constants are compared with experiment and other calculations. We found that the local density approximation results in an energy gap that overestimates the experimental value, in contrast to most materials where the energy gap is underestimated. We propose a simple way to adjust the gap to the experimental value by performing a Slater-Koster fit and then varying the p on-site parameter of Pb. The inclusion of the spin-orbit coupling term in the tight-binding Hamiltonian fit is shown to produce significant changes in the band structure. With these two steps, the calculated band gap is found to be in good agreement with experiment. In the case of PbTe (CsCl) structure, our calculation finds no gap in the bands, contradicting recent experimental data.

Duke Scholars

Author Michael J Mehl Thomas Lord Department of Mechanical Engineering and Materia ...