Spin-dependent dark matter scattering in quasi-two-dimensional magnets

TL;DR

This paper explores the potential of quasi-two-dimensional magnetic materials to detect spin-dependent dark matter through magnon excitations, highlighting their anisotropic properties and sidereal modulation effects.

Contribution

It introduces the concept of using layered magnetic materials as directional detectors for spin-dependent dark matter, with detailed calculations for candidate antiferromagnets.

Findings

Quasi-2D magnets can serve as directional dark matter detectors.

Magnon excitation rates show sidereal modulation due to anisotropic dispersion.

Detection prospects for dark matter in the keV to MeV mass range are demonstrated.

Abstract

We study the prospects of detecting dark matter coupled to the spin of the electron, such that it may scatter and excite magnons - collective excitations of electronic spins. We show that materials exhibiting long-range magnetic order where the spins are coupled only along a plane may act as directional dark matter detectors. These quasi-2D materials possess anisotropic dispersion relations and structure functions which induce a sidereal modulation in the excitation rate. We calculate the expected signal rate for some candidate (anti)ferromagnets, demonstrating a possible route to the direct detection of spin-dependent dark matter in the keV to MeV mass range.