Grain boundary effects on electronic transport in metals

TL;DR

This paper uses quantum simulations to analyze how grain boundary structures affect electron reflectivity in metals like copper and silver, revealing variability and limitations of existing models.

Contribution

It introduces detailed quantum-based methods to study grain boundary reflectivity, highlighting the effects of atomic disorder, orientation, and neighboring boundaries.

Findings

Reflectivity varies significantly with boundary structure.

Disorder and orientation both impact electron reflectivity.

Neighboring grain boundaries influence overall reflectivity.

Abstract

We present quantum-based simulations of single grain boundary reflectivity of electrons in metals, Cu and Ag. We examine twin and non-twin grain boundaries using non-equilibrium Green's function and first principles methods. We also investigate the mechanism of reflectivity in grain boundaries by modeling atomic vacancies, disorder, and orientation and find that the change in grain orientation and disorder in the boundary itself both contribute significantly to reflectivity. We find that grain boundary reflectivity may vary widely depending on the grain boundary structure consistent with experimental results. Finally, we examine the reflectivity from multiple grain boundaries and find that grain boundary reflectivity may depend on neighboring grain boundaries. This study based on detailed numerical techniques reveals some potential limitations in the independent grain boundary assumptions of the Mayadas-Shatzkes model.