Effects of Spin-Orbit Coupling and Thermal Lattice Expansion on the Phonon-limited Resistivity of Pb from First Principles*

In this presentation, we will report the results of calculations on the phonon-limited temperature-dependent electrical resistivity of bulk Pb. Recent developments in computational techniques allow us to make quantitative comparisons between ab initio results of resistivity and experimental data. We use the approach of Wannier interpolation implemented in the EPW code to perform these calculations. The resistivity is computed by iteratively solving the self-consistent linearized Boltzmann Transport Equation. Comparisons are made with the SERTA formulation of the resistivity. We observe that the lattice thermal expansion must be included to better compare to experimental data. We find that including spin-orbit coupling (SOC) affects the results considerably. A softening of the phonon modes at the X point of the Brillouin zone is accentuated with SOC and with the increase of the unit cell volume. That volume change is obtained using the harmonic approximation of the free energy. Here again, we show the effect of including the SOC on the results obtained. Furthermore, we show that the temperature effects on the electronic free energy are negligible compared to the phonon-free energy.