Antiperovskite Highe- Order Topological Insulators for Quantum Sensing Applications

A burgeoning area in quantum sensing is in exploring the correlated, entangled phases found in quantum materials as new pathways to low-threshold sensors. For example, quantum materials have been suggested as next-generation detectors of low-mass dark matter and for THz sensing applications. In this work, we propose a scheme for using symmetry-protected phases in topological materials as a low-threshold sensor. Through ab initio density functional theory calculations, we study antiperovskites, higher-order topological insulators characterized by a Z₄ topological invariant whose surface states are protected by time-reversal and inversion symmetries. We examine how low-energy perturbations can cause topological changes in these materials, and discuss their potential in quantum sensing schemes.