Ferroelastic Altermagnetism

TL;DR

This paper introduces ferroelastic altermagnetism, a novel concept where ferroelastic reorientation controls multistate altermagnetic spin splitting, enabling nonvolatile, strain-controlled spintronic devices using 2D materials.

Contribution

It proposes the concept of ferroelastic altermagnets and demonstrates multistate spin switching in monolayer materials driven by ferroelastic strain.

Findings

Ferroelastic reorientation can switch altermagnetic spin states.

Multistate spin conductivities can be ferroelastically encoded.

Potential for nonvolatile nanomechanical spin switches.

Abstract

Synergizing altermagnetism and other ferroic orders, such as ferroelectric switchable altermagnetism [Phys. Rev. Lett. 134, 106801 (2025) and ibid. 106802 (2025)], offers an effective route to achieve nonvolatile switching of altermagnetic spin splitting. In this work, by synergizing altermagnetism and ferroelasticity, we propose the concept of ferroelastic altermagnets in which the ferroelastic crystal reorientation can drive multistate nonvolatile switching of the altermagnetic spin splitting via altermagnetoelastic effect. Using monolayers RuF4 and CuF2 as material candidates, we demonstrate 2-state and 3-state altermagnetic spin splitting switching as driven by ferroelastic strain states. Transport calculation shows that multistate spin conductivities can be ferroelastically encoded in an ferroelastic altermagnet, thus suggesting the potential of ferroelastic altermagnetic as nonvolatile nanomechanical spin switches. The proposed concept of ferroelastic altermagnetism enriches the emerging landscape of multiferroic altermagnetism, paving a way towards altermagnetic-based straintronic device applications.