Theory and applications of the stress density

TL;DR

This paper introduces the stress density concept within density functional theory, enabling detailed spatial analysis of stress contributions, and demonstrates its effectiveness through applications in surface and interface physics.

Contribution

It presents a practical implementation of stress density in plane wave DFT and shows its advantages over traditional macroscopic stress analysis.

Findings

Stress density provides detailed spatial stress information.

Implementation is efficient within the plane wave ultrasoft pseudopotential method.

Stress density proves more powerful than integrated macroscopic stress.

Abstract

Drawing on the theory of quantum mechanical stress, we introduce the stress density in density functional theory. In analogy with the Chetty-Martin energy density, the stress density provides a spatial resolution of the contributions to the integrated macroscopic stress tensor. We give specific prescriptions for a practical and efficient implementation in the plane wave ultrasoft pseudopotential method within the local-density approximation. We demonstrate the abilities of the stress density studying a set of representative test cases from surface and interface physics. In perspective, the stress density emerges as vastly more powerful and predictive than the integrated macroscopic stress.