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 <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mrow> <a:msub> <a:mrow> <a:mi>MAPbI</a:mi> </a:mrow> <a:mrow> <a:mn>3</a:mn> </a:mrow> </a:msub> </a:mrow> </a:math> , <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"> <c:mrow> <c:msub> <c:mrow> <c:mi>MAPbCl</c:mi> </c:mrow> <c:mrow> <c:mn>3</c:mn> </c:mrow> </c:msub> </c:mrow> </c:math> , and <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"> <e:mrow> <e:msub> <e:mrow> <e:mi>CsPbI</e:mi> </e:mrow> <e:mrow> <e:mn>3</e:mn> </e:mrow> </e:msub> </e:mrow> </e:math> for these purposes. Our findings reveal that <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"> <g:mrow> <g:msub> <g:mrow> <g:mi>CsPbI</g:mi> </g:mrow> <g:mrow> <g:mn>3</g:mn> </g:mrow> </g:msub> </g:mrow> </g:math> is the best material, significantly improving exclusion limits compared to other polar materials. For scattering, <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"> <i:mrow> <i:msub> <i:mrow> <i:mi>CsPbI</i:mi> </i:mrow> <i:mrow> <i:mn>3</i:mn> </i:mrow> </i:msub> </i:mrow> </i:math> can probe dark matter masses down to the keV range. For absorption, it enhances sensitivity to detect dark photon masses below <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"> <k:mo>∼</k:mo> <k:mn>10</k:mn> <k:mtext> </k:mtext> <k:mtext> </k:mtext> <k:mi>meV</k:mi> </k:math> . 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 <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" display="inline"> <m:mrow> <m:msub> <m:mrow> <m:mi>CsPbI</m:mi> </m:mrow> <m:mrow> <m:mn>3</m:mn> </m:mrow> </m:msub> </m:mrow> </m:math> . Moreover, CsI is isotropic while the anisotropic structure of <o:math xmlns:o="http://www.w3.org/1998/Math/MathML" display="inline"> <o:mrow> <o:msub> <o:mrow> <o:mi>CsPbI</o:mi> </o:mrow> <o:mrow> <o:mn>3</o:mn> </o:mrow> </o:msub> </o:mrow> </o:math> enables daily modulation analysis, showing that a significant percentage of daily modulation exceeding 1% is achievable for dark matter masses below 40 keV.