Direct dark matter searches with metal halide perovskites

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 MAPbI3, MAPbCl3, and CsPbI3 for these purposes. Our findings reveal that CsPbI3 is the best material, significantly improving exclusion limits compared to other polar materials. For scattering, CsPbI3 can probe dark matter masses down to the keV range. For absorption, it enhances sensitivity to detect dark photon masses below ~10 meV. The only material that has so far been investigated and that could provide competitive bounds is CsI, which, however, demonstrates lower stability as device platform compared to CsPbI3. Moreover, CsI is isotropic while the anisotropic structure of CsPbI3 enables daily modulation analysis, showing that a significant percentage of daily modulation exceeding 1% is achievable for dark matter masses below 40 keV.