Full magnetoelectric response of Cr2O3 from first principles

TL;DR

This paper calculates the full magnetoelectric response of Cr2O3 from first principles, decomposing contributions and comparing with experimental data, revealing the dominance of different effects in transverse and longitudinal responses.

Contribution

It provides a comprehensive first-principles analysis of both spin and orbital contributions to Cr2O3's magnetoelectric response, including lattice and electronic parts, and clarifies the sign of coupling in magnetic domains.

Findings

Transverse response dominated by spin-lattice and spin-electronic contributions.

Orbital contributions dominate the longitudinal response.

Calculated responses align with some experimental measurements but differ in magnitude for the longitudinal case.

Abstract

The linear magnetoelectric response of Cr2O3 at zero temperature is calculated from first principles by tracking the change in magnetization under a macroscopic electric field. Both the spin and the orbital contributions to the induced magnetization are computed, and in each case the response is decomposed into lattice and electronic parts. We find that the transverse response is dominated by the spin-lattice and spin-electronic contributions, whose calculated values are consistent with static and optical magnetoelectric measurements. In the case of the longitudinal response, orbital contributions dominate over spin contributions, but the net calculated longitudinal response remains much smaller than the experimentally measured one at low temperatures. We also discuss the absolute sign of the magnetoelectric coupling in the two time-reversed magnetic domains of Cr2O3.