Directional detection of light dark matter with polar materials
- Author(s): Griffin, S;
- Knapen, S;
- Lin, T;
- Zurek, KM
- et al.
Published Web Locationhttps://arxiv.org/abs/1807.10291
We consider the direct detection of dark matter (DM) with polar materials, where single production of optical or acoustic phonons gives an excellent reach to the scattering of sub-MeV DM for both scalar and vector mediators. Using density functional theory, we calculate the material-specific matrix elements, focusing on GaAs and sapphire, and show that DM scattering in an anisotropic crystal such as sapphire features a strong directional dependence. For example, for a DM candidate with mass 40 keV and relic abundance set by freeze-in, the daily modulation in the interaction rate can be established at 90% C.L. with a gram year of exposure. Nonthermal dark photon DM in the meV-eV mass range can also be effectively absorbed in polar materials.