Spin-dependent electrical transport at finite temperatures from the first principles

The finite-temperature electrical transport properties depending on the spin are essential for spintronics research focused on developing devices that should operate not only in the conditions of low temperatures. In this study we present a theoretical approach incorporating both chemical and temperature-induced disorder within the coherent potential approximation and the tight-binding linear muffin-tin orbital method, and the linear response theory is used to obtain spin-resolved electrical conductivity. Both nonmagnetic and magnetic materials are studied from the first principles in a wide temperature range. It was found, with neglected magnetic disorder, that vertex corrections to the total conductivity and spin-flip contributions to the conductivity are small; therefore, the spin-resolved coherent conductivities can be used to describe spin-dependent electrical transport. The developed formalism is applied to pure nonmagnetic platinum and to ferromagnetic random Cu-Ni alloys. For the latter system, the spin polarization of the current is nearly constant in the examined temperature range.