Direct Dark Matter searches with Metal Halide Perovskites

Abstract

Polar materials with optical phonons in the meV range are excellent candidates for both dark matter direct detection (via dark photon-mediated scattering) and light dark matter absorption. In this study, we propose, for the first time, the metal halide perovskites MAPbI${}_3$, MAPbCl${}_3$, and CsPbI${}_3$ for these purposes. Our findings reveal that CsPbI${}_3$ is the best material, significantly improving exclusion limits compared to other polar materials. For scattering, CsPbI${}_3$ can probe dark matter masses down to the keV range. For absorption, it enhances sensitivity to detect dark photon masses below $\sim 10\mathrm{meV}$. The only material which has so far been investigated and that could provide competitive bounds is CsI, which, however, is challenging to grow in kilogram-scale sizes due to its considerably lower stability compared to CsPbI${}_3$. Moreover, CsI is isotropic while the anisotropic structure of CsPbI${}_3$ enables daily modulation analysis, showing that a significant percentage of daily modulation exceeding 1% is achievable for dark matter masses below $40\mathrm{keV}$.