Spin-Neutral Tunneling Anomalous Hall Effect

TL;DR

This paper predicts a novel spin-neutral tunneling anomalous Hall effect in antiferromagnetic tunnel junctions driven by symmetry mismatch and spin-orbit coupling, enabling Ne9el vector detection without net spin polarization.

Contribution

It introduces the concept of spin-neutral tunneling AHE in AFM junctions, a novel mechanism distinct from conventional spin-polarized AHE.

Findings

Predicts a sizable spin-neutral TAHE in AFM tunnel junctions.

Shows Hall currents are reversible by Ne9el vector switching.

Hall angle comparable to conventional AHE materials.

Abstract

Anomalous Hall effect (AHE) is a fundamental spin-dependent transport property that is widely used in spintronics. It is generally expected that currents carrying net spin polarization are required to drive the AHE. Here we demonstrate that, in contrast to this common expectation, a spin-neutral tunneling AHE (TAHE), i.e. a TAHE driven by spin-neutral currents, can be realized in an antiferromagnetic (AFM) tunnel junction where an AFM electrode with a non-spin-degenerate Fermi surface and a normal metal electrode are separated by a non-magnetic barrier with strong spin-orbit coupling (SOC). The symmetry mismatch between the AFM electrode and the SOC barrier results in an asymmetric spin-dependent momentum filtering of the spin-neutral longitudinal current generating the transverse Hall current in each electrode. We predict a sizable spin-neutral TAHE in an AFM tunnel junction with a RuO$_{2}$-type AFM electrode and a SnTe-type SOC barrier and show that the Hall currents are reversible by the N\'eel vector switching. With the Hall angle being comparable to that in conventional AHE bulk materials, the predicted spin-neutral TAHE can be used for the N\'eel vector detection in antiferromagnetic spintronics.