Electron doping and magnetic moment formation in N- and C-doped MgO

TL;DR

This study uses advanced computational methods to explore how electron doping affects magnetic moments in N- and C-doped MgO, revealing that magnetic moments are robust and highly localized despite environmental changes.

Contribution

It demonstrates that magnetic moments in N- and C-doped MgO are stable against electron doping and emphasizes the localized nature of these moments, challenging carrier-mediated magnetism models.

Findings

Magnetic moments are robust against electron doping.

Local symmetry around dopants can vary, leading to different geometries.

Magnetic moments are highly localized, unlikely to be carrier-mediated.

Abstract

The formation of the magnetic moment in C- and N-doped MgO is the result of a delicate interplay between Hund's coupling, hybridization and Jahn-Teller distortion. The balance depends on a number of environmental variables including electron doping. We investigate such a dependence by self-interaction corrected density functional theory and we find that the moment formation is robust with respect to electron doping. In contrast, the local symmetry around the dopant is more fragile and two different geometries can be stabilized. Crucially the magnetic moment is always extremely localized, making any carrier mediated picture of magnetism in d^0 magnets unlikely.