Phase-Rotated Altermagnets as Chern Valves for Topological Transport

TL;DR

This paper introduces a novel method to control topological transport in a two-terminal device by rotating the crystalline phase of altermagnetic electrodes, enabling programmable conductance and thermoelectric properties without external magnetic fields.

Contribution

It demonstrates a phase-rotation technique in altermagnets to tune topological edge states and transport properties in a topological-insulator interface, providing a new low-dissipation control mechanism.

Findings

Reversible switching of conductance steps via phase rotation.

Quantized topological transport robust to moderate disorder.

Control of thermoelectric coefficients without magnetic fields.

Abstract

Motivated by the emerging control of Berry-curvature textures in altermagnets, we explore a two-terminal configuration where a topological-insulator film is interfaced with two altermagnetic electrodes whose crystalline phases can be rotated independently. The proximity coupling imprints each momentum-dependent of the altermagnet spin texture onto the Dirac surface states, giving rise to an angular mass whose sign follows the lattice orientation. Adjusting the phase of one electrode redefines this mass pattern, thereby tuning the number and spatial distribution of chiral edge channels. This results in discrete conductance steps and a reversible inversion of the thermoelectric coefficient-achieved without external magnetic fields or net magnetization. A compact Dirac model captures both the quantized switching and its resilience to moderate disorder. Overall, this symmetry-driven mechanism provides a practical and low-dissipation route to programmable topological transport via lattice rotation.