Novel Phonon-Based Topological Sensors for Dark Matter Detection

Dark matter (DM) has so far evaded direct detection. Next-generation DM searches are stretching to lower masses than weakly interacting massive particles (WIMPs), facilitated by increasing detector sensitivity and new proposals of detection in quantum materials. Quantum materials offer an exciting platform for such low-mass DM detection owing to the match of relevant energy scales and the large number of degrees of freedom that can be exploited for DM coupling. In this work, we propose a novel phonon-based quantum sensing mechanism in topological quantum materials and explore low-mass DM detection as a possible application. Through ab initio density functional theory and GW calculations, we study higher-order topological insulators (HOTI) whose hinge states are protected by inversion and time-reversal symmetries. With antiperovskites as our representative HOTIs, we elucidate the effects of non-equilibrium optical phonons on these materials' bulk, surface, and hinge electronic structures, and further examine DM-phonon coupling via different mediators.