Fully resolved currents from quantum transport calculations

TL;DR

This paper presents a method to extract and visualize local current distributions in multilayer materials using relativistic quantum transport calculations, revealing different behaviors in classical and Knudsen regimes.

Contribution

It introduces a novel approach to interpolate quantum mechanical scattering data onto a 3D grid for detailed current analysis in multilayer systems.

Findings

Transport inside metals can be described with a single resistivity in the classical limit.

Current density exhibits spatial dependence and anomalous dips at interfaces in the Knudsen limit.

Temperature-dependent lattice disorder affects current distribution in thin films.

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 temperature-dependent lattice disorder. The current flow is studied in the "classical" and "Knudsen" limits determined by the sample thickness relative to the mean free path $\lambda$, 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 $\rho$ combined with a linear variation of $\rho$ at the interface while the Knudsen limit indicates a strong spatial dependence of $\rho$ inside a metal and an anomalous dip of the current density at the interface which is accentuated in a region where transient shunting persists.