Unconventional Materials for Light Dark Matter Detection

TL;DR

This paper explores unconventional materials like TiSe$_2$, Sr$_2$RuO$_4$, and doped diamond as highly sensitive detectors for light dark matter, leveraging their unique low-energy plasmon modes to improve detection capabilities.

Contribution

It introduces novel detector materials with low-energy plasmon modes and demonstrates their potential to significantly enhance light dark matter detection sensitivity.

Findings

Materials exhibit low-energy plasmon modes suitable for dark matter detection.

Detectors based on these materials could outperform existing proposals by several orders of magnitude.

Anisotropic responses enable directional detection, enhancing detection capabilities.

Abstract

We propose the use of several unconventional materials as detectors for dark matter with mass beneath the MeV scale. These include the transition-metal dichalcogenide TiSe$_2$ hosting a low-energy plasmon in the charge-density-wave phase, Sr$_2$RuO$_4$ containing a low-energy acoustic demon mode, and hole-doped diamond with tunable optical and acoustic plasmon frequencies. We perform first-principles density functional theory computations of their loss functions at non-vanishing momenta and establish their reach into light dark matter parameter space. We show that due to intense low-energy plasmon modes -- of different microscopic origin in each -- the reach of detectors based on these materials could surpass existing proposals by several orders of magnitude for both dark matter scattering and absorption on electrons. The anisotropic response of these materials, which enables directional detection, renders them exceptionally strong detector candidates, motivating the design and fabrication of future devices.