Nonreciprocal transport in a bilayer of MnBi2Te4 and Pt

TL;DR

This study reports nonreciprocal transport in a bilayer of magnetic topological insulator MnBi2Te4 and platinum, revealing how surface electron-magnon interactions induce current-direction-dependent resistance below the magnetic ordering temperature.

Contribution

It demonstrates nonreciprocal transport in MnBi2Te4/Pt bilayers and links it to surface magnetism and electron-magnon scattering, providing new insights into magnetic topological insulators.

Findings

Nonreciprocal resistance observed below Néel temperature.

Nonreciprocity linked to surface electron-magnon interactions.

Angular dependence indicates asymmetric electron scattering.

Abstract

MnBi2Te4 (MBT) is the first intrinsic magnetic topological insulator with the interaction of spin-momentum locked surface electrons and intrinsic magnetism, and it exhibits novel magnetic and topological phenomena. Recent studies suggested that the interaction of electrons and magnetism can be affected by the Mn-doped Bi2Te3 phase at the surface due to inevitable structural defects. Here we report an observation of nonreciprocal transport, i.e. current-direction-dependent resistance, in a bilayer composed of antiferromagnetic MBT and nonmagnetic Pt. The emergence of the nonreciprocal response below the N\'eel temperature confirms a correlation between nonreciprocity and intrinsic magnetism in the surface state of MBT. The angular dependence of the nonreciprocal transport indicates that nonreciprocal response originates from the asymmetry scattering of electrons at the surface of MBT mediated by magnon. Our work provides an insight into nonreciprocity arising from the correlation between magnetism and Dirac surface electrons in intrinsic magnetic topological insulators.