All-Electrical Layer-Spintronics in Altermagnetic Bilayer

TL;DR

This paper introduces a novel all-electrical method for manipulating spin-polarized currents in altermagnetic bilayers, utilizing layer-spin locking and electric fields, demonstrated through first-principles calculations on CrS bilayers.

Contribution

It proposes the concept of layer-spintronics combining altermagnetism and bilayer stacking for efficient electrical control of spin polarization.

Findings

Achieves up to 87% reversible spin polarization at room temperature.

Demonstrates electric field can fully reverse spin polarization.

Introduces layer-spin locking mechanism in CrS bilayer.

Abstract

Electrical manipulation of spin-polarized current is highly desirable yet tremendously challenging in developing ultracompact spintronic device technology. Here we propose a scheme to realize the all-electrical manipulation of spin-polarized current in an altermagnetic bilayer. Such a bilayer system can host layer-spin locking, in which one layer hosts a spin-polarized current while the other layer hosts a current with opposite spin polarization. An out-of-plane electric field breaks the layer degeneracy, leading to a gate-tunable spin-polarized current whose polarization can be fully reversed upon flipping the polarity of the electric field. Using first-principles calculations, we show that CrS bilayer with C-type antiferromagnetic exchange interaction exhibits a hidden layer-spin locking mechanism that enables the spin polarization of the transport current to be electrically manipulated via the layer degree of freedom. We demonstrate that sign-reversible spin polarization as high as 87% can be achieved at room temperature. This work presents the pioneering concept of layer-spintronics which synergizes altermagnetism and bilayer stacking to achieve efficient electrical control of spin.