Sliding Ferroelectricity Driven Spin-Layertronics in Altermagnetic Multilayers

TL;DR

This paper introduces a novel mechanism using sliding ferroelectricity in altermagnetic multilayers to enable nonvolatile electrical control of spin and layer states, paving the way for advanced spintronic devices.

Contribution

It demonstrates how interlayer translation in altermagnetic bilayers can switch ferroelectric polarization and control spin splitting, a new approach for spin-layertronics.

Findings

Interlayer translation induces switchable ferroelectric polarization.

Ferroelectric switching reverses altermagnetic spin splitting.

Multiple polarization states enable multi-state logic applications.

Abstract

The synergy of ferroicity with altermagnetism offers a novel platform for designing multifunctional altermagnetic-spintronic device technology. In this work, we propose a mechanism to achieve nonvolatile electrical manipulation of spin and layer degrees of freedom in an altermagnetic bilayer via sliding ferroelectricity. Using first-principles calculations, we show that an interlayer translation can induce a switchable out-of-plane ferroelectric polarization in bilayer CuF2, which directly couples to and reverses the d-wave altermagnetic spin splitting. Notably, the altermangetic spin splitting is layer-locked, the sliding ferroelectricity-driven switching thus embodying a nonvolatile spin-layertronics functionality that couples spin-polarized transport and layer degree of freedom in a single platform. We show that in quadrilayer CuF2, four polarization states are identified which may offer multi-state logic device applications. These findings establish sliding ferroelectricity as a versatile tool for designing voltage-controlled, high-speed and energy-efficient spin-layertronic devices based on altermagnets.