Fully compensated and uncompensated ferrimagnetic ferrovalley semiconductors

TL;DR

This paper explores the transformation from altermagnets to fully compensated ferrimagnets, proposing a new ferrimagnetic monolayer with large valley polarization and revealing a unique valley Hall effect, advancing valleytronics applications.

Contribution

It introduces a mechanism for strain-driven transformation from altermagnets to ferrimagnets and proposes a new ferrimagnetic monolayer with giant valley polarization.

Findings

Uniaxial strain induces transformation from altermagnet to ferrimagnet.

Proposed monolayer VCrSeTeO achieves over 400 meV valley polarization.

Reversal of valley Hall voltage within the same valley in VCrSeTeO.

Abstract

Altermagnets (AMs) and fully compensated ferrimagnets (FC-FIMs) are emerging classes of magnetic materials that combine the advantages of antiferromagnets and ferromagnets. Here, we elucidate the mechanism behind the uniaxial strain-driven transformation from AM to FC-FIM and find that the accompanying non-relativistic valley polarization is positively correlated with the net magnetic moment between magnetic atoms in opposite spin sublattices. We then propose an uncompensated ferrimagnetic monolayer VCrSeTeO to achieve large intrinsic valley polarization. Spin-orbit coupling (SOC) is shown to further increase the valley polarization to over 400 meV under uniaxial strains and the reason is explained in terms of SOC perturbation theorem. Furthermore, we reveal a distinctive anomalous valley Hall effect in which the valley Hall voltage is reversed within the same valley in ferrimagnet VCrSeTeO. This work proposes a strategy for realizing giant valley polarization and provides theoretical guidance for the application of ferrimagnetic ferrovalley semiconductors derived from altermagnets in valleytronics.