Effect of spin-orbit interactions on the structural stability, thermodynamic properties, and transport properties of lead under pressure

Abstract

The paper investigates the role of spin-orbit interaction in the prediction of structural stability, lattice dynamics, elasticity, thermodynamic and transport properties (electrical resistivity and thermal conductivity) of lead under pressure with the FP-LMTO (full-potential linear-muffin-tin orbital) method for the first-principles band structure calculations. Our calculations were carried out for three polymorphous lead modifications (fcc, hcp, and bcc) in generalized gradient approximation with the exchange-correlation functional PBEsol. They suggest that compared to the scalar-relativistic calculation, the account for the SO effects insignificantly influences the compressibility of Pb. At the same time, in the calculation of phonon spectra and transport properties, the role of SO interaction is important, at least, for $P\ensuremath{\lesssim}150$ GPa. At higher pressures, the contribution from SO interaction reduces but not vanishes. As for the relative structural stability, our studies show that SO effects influence weakly the pressure of the $\mathrm{fcc}\ensuremath{\rightarrow}\mathrm{hcp}$ transition and much higher the pressure of the $\mathrm{hcp}\ensuremath{\rightarrow}\mathrm{bcc}$ transition.