Strain and ferroelectric polarization tune magnetic phase transition and anomalous Hall effect in Ti2Se2S/PbTe heterostructure with Rashba effect

Abstract

Altermagnets have attracted considerable attention for uniting the advantages of ferromagnets and antiferromagnets and for their promise in advancing spintronics. However, investigations focused on tuning the properties of two-dimensional altermagnets, particularly regarding magnetic phase transition, electronic properties, and anomalous Hall conductivity, remain comparatively limited. Here, we propose an approach to manipulate the magnetic ground state, metal to half-metal transition, Rashba spin splitting, and anomalous Hall conductivity of an altermagnet by ferroelectric reversal. To address experimental fabrication and application needs, we systematically investigated three typical stacking configurations under three strain conditions in the Ti2Se2S/PbTe van der Waals heterostructures, confirming the feasibility of this approach. Under the strong compressive strain, the ferroelectric polarization switching not only tunes the transition from the altermagnetic to ferromagnetic states but also regulates the magnitude and direction of the anomalous Hall conductivity. Importantly, interface effects can induce pronounced Rashba splitting in all altermagnetic states. When the strain reaches a moderate compressive level, although the ferromagnetic state persists under all polarization directions, switching the ferroelectric polarization induces a half-metal to metal transition. While the anomalous Hall conductivity shows little change, the Berry curvature is fully reconfigured by polarization switching. Without applied strain, all configurations show a ferromagnetic metallic state. The dramatic change in anomalous Hall conductivity upon polarization switching originates from a modification in the occupation of spin-polarized states. Our findings provide a direction for investigating altermagnetic devices with implications for nonvolatile, ultrafast, and low-power spintronic devices.