Magnetic Structure of CoO

TL;DR

This paper provides theoretical evidence confirming the existence of a specific multi-spin-axis magnetic structure in CoO, explaining associated lattice distortions and its relation to the material's Mott insulating behavior.

Contribution

It demonstrates the existence of the proposed multi-spin-axis magnetic structure in CoO and links it to observed lattice distortions and electronic properties.

Findings

Confirmation of the multi-spin-axis magnetic structure in CoO

Explanation of tetragonal and monoclinic distortions in CoO

Identification of atomic-like electron motion as key to Mott insulating state

Abstract

The paper reports theoretical evidence that the multi-spin-axis magnetic structure proposed in 1964 by van Laar actually does exist in CoO. This tetragonal spin arrangement produces both the strong tetragonal and the weaker monoclinic distortion experimentally observed in this material. The monoclinic distortion is proposed to be a "monoclinic-like" distortion of the array of the oxygen atoms, comparable with the rhombohedral-like distortion of the oxygen atoms recently proposed to be present in NiO and MnO. The monoclinic-like distortion has no influence on the tetragonal magnetic structure which is generated by a special nonadiabatic atomic-like motion of the electrons near the Fermi level. It is argued that it is this special atomic-like motion which qualifies CoO to be a Mott insulator.