Electroacoustic waves in a PT-symmetric piezoelectric structure near the exceptional point

The spectral properties of gap electroacoustic waves in PT-symmetric piezoelectric structures of symmetry class 6 are investigated theoretically. It was found out that, at a certain level of loss and gain in piezoelectrics, the symmetric and antisymmetric modes intersect. The intersection point defines an exceptional point of the PT-symmetric structure. It was shown that the frequency dependence of the amplitude at the exceptional point has an extremely narrow resonance peak, which opens up the possibility of creating supersensitive sensors based on PT-symmetric physical structures.