Crystal field calculations for transition metal ions by application of an opposing potential

TL;DR

This paper introduces an ab initio method called opposing crystal potential (OCP) for calculating crystal field parameters of transition metal ions in insulators, using constrained density functional theory to achieve spherical d-electron distributions.

Contribution

The paper presents a novel ab initio approach, OCP, that accurately computes crystal field parameters by applying a cancellation potential, improving agreement with experimental data.

Findings

OCP yields crystal field parameters consistent with experiments.

The method successfully applied to Mn ions in various insulators.

Provides a new tool for studying transition metal impurities.

Abstract

We propose a fully ab initio method, the opposing crystal potential (OCP), to calculate the crystal field parameters of transition metal impurities in insulator hosts. Through constrained density functional calculations, OCP obtains the constraining Lagrange multipliers, which act as cancellation potential against the crystal field and lead to spherical $d$-electron distribution. The method is applied to several insulators doped with Mn$^{4+}$ and Mn$^{2+}$ ions and shown to be in good agreement with experiment.