Non-linear anomalous Edelstein response at altermagnetic interfaces

TL;DR

This paper explores the unique non-linear spin-to-charge conversion phenomena at altermagnetic interfaces, revealing anomalous Edelstein effects and electric-field-driven magnetization driven by complex spin textures.

Contribution

It introduces the concept of anomalous non-linear Edelstein responses at altermagnetic surfaces, combining theoretical modeling with ab-initio calculations to predict novel spintronic effects.

Findings

Identification of anomalous transverse Edelstein effect in altermagnets

Prediction of electric-field-driven out-of-plane magnetization

Suppression of linear Rashba-Edelstein response by altermagnetic order

Abstract

In altermagnets, time-reversal symmetry breaking spin-polarizes electronic states, while total magnetization remains zero. In addition, at altermagnetic surfaces Rashba-spin orbit coupling is activated due to broken inversion symmetry, introducing a competing spin-momentum locking interaction. Here we show that their interplay leads to the formation of complex, chiral spin textures that offer novel, non-linear spin-to-charge conversion properties. Whereas altermagnetic order suppresses the canonical linear in-plane Rashba-Edelstein response, we establish the presence of an \textit{anomalous} transversal Edelstein effect for planar applied electric and magnetic field, or alternatively, an in-plane magnetization. Additionally, we predict a purely electric-field-driven non-linear out-of-plane magnetization. We compute the anomalous response within a general altermagnet $d$-wave model, with parameters extracted from the ab-initio electronic structure of an altermagnetic bilayer. Our results suggest altermagnetic surfaces as a promising platform for unconventional spintronic functionalities.