Weakly spin-dependent band structures of antiferromagnetic perovskite LaMO$_3$ (M = Cr, Mn, Fe)

TL;DR

This study uses first-principles DFT calculations to analyze spin-dependent band structures in antiferromagnetic LaMO$_3$ compounds, revealing a simple symmetry-based rule for spin splitting and its implications for spin current applications.

Contribution

It introduces a straightforward symmetry rule to identify spin splitting in AFM LaMO$_3$ compounds and discusses its potential benefit for electrode applications.

Findings

Spin splitting is very small in the most stable configurations.

A simple symmetry rule determines which wave vectors exhibit spin splitting.

The spin current direction is independent of the spin configuration.

Abstract

We investigate spin-dependent electronic states of antiferromagnetic (AFM) lanthanum chromite (LaCrO$_3$), lanthanum manganite (LaMnO$_3$), and lanthanum ferrite (LaFeO$_3$) using spin-polarized first-principles density functional theory (DFT) with Hubbard U correction. The band structures are calculated for 15 types of their different AFM structures. It is verified for these structures that there is a very simple rule to identify which wave number k exhibits spin splitting or degeneracy in the band structure. This rule uses the symmetry operations that map the up-spin atoms onto the down-spin atoms. The resulting spin splitting is very small for the most stable spin configuration of the most stable experimental structure. We discuss a plausible benefit of this characteristic, i.e., the direction-independence of the spin current, in electrode applications.