Acoustic topological states on RF Piezo-Electric MEMS Technology and possible sensing appli- cations

Since the discovery of the Quantum Hall effect and, consequently, the topo??logical states, the interest for devices exploiting this kind of phenomena has grown significantly. These types of state are characterized by a surprising en??ergy localization resulting in a high-quality factor. In the first part of this work, some possible topologies presented can be used to induce the creation of edge and corner states. With FEM simulations, in particular COMSOL, the disper??sion relations of the single cells and supercells have been studied both in 2D and 3D. The topological states have been induced because of the breaking of the symmetry in specific directions. To prove the existence of the topological state, the Berry curvature has been calculated. The Berry curvature is a pa??rameter directly linked to the topological nature of the states in a 3D system. In the second part of this work, some possible layouts are shown to convert the topological state into an electric signal. To perform this,SiO2 periodic struc??tures have been deposited on top of a piezo-electric material (AlScN) which can convert the RF mechanical signal into a RF electronic signal in the tens of MHz range. This kind of signal could be used as a sensor for various parameters, such as: acceleration, stress, vibration, temperature and even infrared