Non-collinear density functional theory

TL;DR

This paper introduces a novel method to extend collinear density functional theory to non-collinear cases, ensuring correct limits, stability, and applicability to spin dynamics.

Contribution

It proposes a generalization approach that guarantees the exact collinear limit, stable derivatives, and applicability to spin dynamics in non-collinear density functional theory.

Findings

Ensures correct collinear limit in non-collinear functionals

Provides stable and well-defined functional derivatives

Enables applications in spin dynamics

Abstract

An approach to generalize any kind of collinear functionals in density functional theory to non-collinear functionals is proposed. This approach, for the very first time, satisfies the correct collinear limit for any kind of functionals, guaranteeing that the exact collinear functional after generalized is still exact for collinear spins. Besides, it has well-defined and numerically stable functional derivatives, a desired feature for non-collinear and spin-flip time-dependent density functional theory. Furthermore, it provides local torque, hinting at its applications in spin dynamics.