Band structure of nickel: Spin-orbit coupling, the Fermi surface, and the optical conductivity

TLDR

The study extends prior tight‑binding band calculations for ferromagnetic nickel by incorporating spin‑orbit coupling. The authors employed an Xα exchange scheme (α = 2/3), sampled 1357 k‑points in 1/16th of the Brillouin zone with spin aligned along [001], computed the density of states via a hybrid method, and evaluated interband conductivity tensor elements from spin‑orbit‑coupled wave functions. They mapped the Fermi surface cross sections, extracted effective masses, and reported both diagonal and off‑diagonal components of the conductivity tensor.

Abstract

A previous self-consistent calculation of energy bands in ferromagnetic nickel using the tight-binding method has been extended to include spin-orbit coupling. Exchange was incorporated using the $X\ensuremath{\alpha}$ method with $\ensuremath{\alpha}=\frac{2}{3}$. Energy levels were obtained at 1357 points in 1/16th of the Brillouin zone. The direction of spin alignment was taken to be [001]. The density of states was computed by a hybrid method. Cross sections of the Fermi surface were determined, and effective masses were obtained. The interband contribution to the conductivity tensor was calculated using matrix elements computed from wave functions including spin-orbit coupling. Results were obtained for both the diagonal and the off-diagonal elements of the conductivity tensor.