Directional Detection of Dark Matter with Two-Dimensional Targets

TL;DR

This paper proposes using two-dimensional materials like graphene for direct dark matter detection, highlighting their potential for high sensitivity and directional detection capabilities, especially for sub-GeV dark matter particles.

Contribution

It introduces the concept of using 2D materials as targets for dark matter detection, demonstrating their comparable sensitivity to traditional semiconductors and their unique directional detection advantage.

Findings

Graphene can detect MeV to GeV dark matter with sensitivity similar to silicon and germanium.

Two-dimensional targets enable directional detection by preserving angular information of ejected electrons.

Implementation via PTOLEMY offers a new avenue for sub-GeV dark matter detection.

Abstract

We propose two-dimensional materials as targets for direct detection of dark matter. Using graphene as an example, we focus on the case where dark matter scattering deposits sufficient energy on a valence-band electron to eject it from the target. We show that the sensitivity of graphene to dark matter of MeV to GeV mass can be comparable, for similar exposure and background levels, to that of semiconductor targets such as silicon and germanium. Moreover, a two-dimensional target is an excellent directional detector, as the ejected electron retains information about the angular dependence of the incident dark matter particle. This proposal can be implemented by the PTOLEMY experiment, presenting for the first time an opportunity for directional detection of sub-GeV dark matter.