Electric-Field-induced Two-Dimensional Fully Compensated Ferrimagnetism and Emergent Transport Phenomena

TL;DR

This paper demonstrates that applying an out-of-plane electric field to monolayer CoS and CoSe can induce fully compensated ferrimagnetism with spin-split bands, enabling novel spintronic phenomena.

Contribution

It reveals a method to control ferrimagnetic states in 2D materials using electric fields, expanding the understanding of spin-split electronic structures in zero-magnetization systems.

Findings

Electric field induces ferrimagnetism in monolayer CoS and CoSe.

Induced states exhibit fully spin-polarized currents and anomalous Hall effects.

Electric-field-controlled ferrimagnetism enables potential spintronic applications.

Abstract

The recent discovery of altermagnetism has demonstrated that spin-split electronic band structures can emerge in magnetic systems with zero net magnetization. In contrast, fully compensated ferrimagnetic (fFIM) systems remain far less explored, despite exhibiting similar characteristics such as vanishing magnetization and spin-split bands. Here, based on first-principles calculations combined with theoretical analysis, we demonstrate that monolayer CoS and CoSe can be driven into fFIM states by an external electric field. These materials possess collinear antiferromagnetic ground states with out-of-plane N\'eel vectors, and their electronic bands are spin degenerate due to $\mathcal{PT}$ symmetry. When an out-of-plane electric field is applied, $\mathcal{PT}$ symmetry is broken, inducing fFIM states with pronounced spin splitting. Moreover, we show that the resulting fFIM states host fully spin-polarized currents, anomalous Hall effects, and magneto-optical Kerr and Faraday effects. Our results establish monolayer CoS and CoSe as promising platforms for electric-field-controlled fFIM states and spintronic applications.