Application of the NRL tight-binding method to the heavy elements Pb and Po

We have applied the NRL tight-binding (TB) method to study the mechanical and electronic properties of the heavy elements Pb and Po. The predicted properties include ground-state structure, electronic band structure and elastic moduli. Phonon-dispersion curves at T=0 K were also determined. As demonstrated in this paper, the results are in good agreement with the full potential linearized augmented plane wave calculations and the available experimental data. In addition, we performed molecular-dynamics simulations to obtain various temperature-dependent quantities of Pb such as the atomic mean-square displacement, Debye-Waller factor and thermal expansion coefficient. With our TB we have also calculated the vacancy formation energy of Pb. Finally, we report on the effects of spin-orbit coupling, through our TB scheme, on electronic structure and energetic properties.