Electric control of Dirac quasiparticles by spin-orbit torque in an antiferromagnet

TL;DR

This paper predicts that Dirac quasiparticles in antiferromagnets can be controlled via spin-orbit torque-induced reorientation of the Ne9el vector, enabling topological transitions and anisotropic magnetoresistance.

Contribution

It introduces a symmetry-based framework for controlling Dirac quasiparticles in antiferromagnets using spin-orbit torque, demonstrated in CuMnAs.

Findings

Dirac band crossings are protected by non-symmorphic symmetry.

Reorientation of the Ne9el vector switches Dirac crossings on and off.

Predicted topological metal-insulator transition driven by Ne9el vector reorientation.

Abstract

Spin-orbitronics and Dirac quasiparticles are two fields of condensed matter physics initiated independently about a decade ago. Here we predict that Dirac quasiparticles can be controlled by the spin-orbit torque reorientation of the N\'{e}el vector in an antiferromagnet. Using CuMnAs as an example, we formulate symmetry criteria allowing for the co-existence of Dirac quasiparticles and N\'{e}el spin-orbit torques. We identify the non-symmorphic crystal symmetry protection of Dirac band crossings whose on and off switching is mediated by the N\'{e}el vector reorientation. We predict that this concept, verified by minimal model and density functional calculations in the CuMnAs semimetal antiferromagnet, can lead to a topological metal-insulator transition driven by the N\'{e}el vector and to the corresponding topological anisotropic magnetoresistance.