Prediction of Tunable Spin-Orbit Gapped Materials for Dark Matter Detection

TL;DR

This paper proposes spin-orbit semiconductors with tunable meV-scale band gaps as promising targets for low-mass dark matter detection, using DFT predictions of their electronic and topological properties.

Contribution

It introduces spin-orbit semiconductors as novel dark matter detection materials and predicts suitable candidates like tin pnictides with tunable gaps.

Findings

Tin pnictides have tunable meV-scale band gaps.

Spin-orbit semiconductors exhibit anisotropic Fermi velocities.

DFT predictions highlight potential pitfalls in narrow-gap material modeling.

Abstract

New ideas for low-mass dark matter direct detection suggest that narrow band gap materials, such as Dirac semiconductors, are sensitive to the absorption of meV dark matter or the scattering of keV dark matter. Here we propose spin-orbit semiconductors - materials whose band gap arises due to spin-orbit coupling - as low-mass dark matter targets owing to their ~10 meV band gaps. We present three material families that are predicted to be spin-orbit semiconductors using Density Functional Theory (DFT), assess their electronic and topological features, and evaluate their use as low-mass dark matter targets. In particular, we find that that the tin pnictide compounds are especially suitable having a tunable range of meV-scale band gaps with anisotropic Fermi velocities allowing directional detection. Finally, we address the pitfalls in the DFT methods that must be considered in the ab initio prediction of narrow-gapped materials, including those close to the topological critical point.