Perovskite as a spin current generator

TL;DR

This paper theoretically demonstrates that perovskite materials can generate pure spin currents via a mechanism that does not rely on spin-orbit coupling or ferromagnetism, utilizing their unique antiferromagnetic band structures.

Contribution

It introduces a novel spin current generation mechanism in perovskites based on collinear antiferromagnetic states and lattice distortions, expanding potential spintronic applications.

Findings

Pure spin current can be induced by electric fields in perovskite antiferromagnets.

The mechanism relies on anisotropic electron transfer and lattice distortion effects.

Symmetry analysis supports the proposed spin current generation process.

Abstract

We theoretically show that materials with perovskite-type crystal structures provide a platform for spin current generation, taking advantage of a mechanism requiring neither the spin-orbit coupling nor a ferromagnetic moment, but is based on spin-split band structures in certain kinds of collinear antiferromagnetic states. By investigating a multiband Hubbard model for transition metal compounds by means of the Hartree-Fock approximation and the Boltzmann transport theory, we find that a pure spin current is induced by an electric field applied to a C-type antiferromagnetic metallic phase. The spin current generation originates from a cooperative effect of spatially anisotropic electron transfer integrals owing to the GdFeO$_3$-type lattice distortion, which is ubiquitous in many perovskites, and the collinear spin configuration. We discuss our finding from the symmetry point of view, in comparison with other spin current generator candidates with collinear antiferomagnetism. We also propose several ways to detect the phenomenon in candidate perovskite materials.