Chiral phonons in metal-organic frameworks as quantum sensors for the direct detection of dark matter

We investigate a new quantum sensor for dark matter direct detection with sub-eV sensitivity, focusing on several candidate materials that potentially host chiral phonons with large magnetic moments that can be directly read out with an external magnetometer. We focus on metal-organic frameworks (MOFs) as possible candidate materials for single chiral phonon detection due to their noncentrosymmetric structure, tunability, and the ability to host these excitations in stable acoustic bands. We identify several promising candidates and compare their projected dark matter detection sensitivity for all possible interactions identified within effective field theory. We establish that the expected sensitivity does not depend heavily on the specific choice of the MOF, enabling us to tailor the final material composition to facilitate the magnetic readout. We then propose a prototype setup able to test the direct readout of a chiral phonon sensor with a surface-integrated magnetometer.