Fully resolved currents from quantum transport calculations

Abstract

We extract local current distributions from interatomic currents calculated using a fully relativistic quantum mechanical scattering formalism by interpolation onto a three-dimensional grid. The method is illustrated with calculations for Pt|Ir and Pt|Au multilayers as well as for thin films of Pt and Au that include temperaturedependent lattice disorder. The current flow is studied in the "classical" and "Knudsen" limits determined by the sample thickness relative to the mean free path λ, introducing current streamlines to visualize the results. For periodic multilayers, our results in the classical limit reveal that transport inside a metal can be described using a single value of resistivity ρ combined with a linear variation of ρ at the interface while the Knudsen limit indicates a strong spatial dependence of ρ inside a metal and an anomalous dip of the current density at the interface which is accentuated in a region where shunting is incomplete.

Calculating interface transport parameters at finite temperatures: Nonmagnetic interfaces

“…Within the framework of density functional theory [52,53], we solve the quantum mechanical scattering problem [54] for a general two terminal L|S|R configuration consisting of an NM|NM scattering region (S) embedded between ballistic left (L) and right (R) leads (Au or Pt) using a wave-function matching method [55] implemented [45,56] with a tight-binding (TB) muffintin orbital (MTO) basis in the atomic spheres approximation (ASA) [57][58][59] and generalized to include SOC and noncollinearity [26] as well as temperature induced lattice and spin disorder [27,28]. The solution yields the scattering matrix S, from which we can directly calculate the conductance [54,60], as well as the full quantum mechanical wave function throughout the scattering region with which we can calculate position dependent charge and spin currents [10,24,61]. Atomic sphere (AS) potentials for Au, Pt and Pd are generated using the Stuttgart TB-LMTO code.…”