Thermal switching of ultrasonic waves in two-dimensional solid/fluid phononic crystals

We have made a theoretical study of temperature effects on two-dimensional Quartz/Ethanol phononic crystal structure in submicrometer scale. By introducing materials with adequate contrast between their elastic constants, sound velocity and mass density, it is feasible to modulate the phononic bandgap which means a range of fRequency that no waves can pass through the structure. The thermal tunability of band structure in megahertz range is demonstrated by the analysis of the band structure using finite element method. Considering the thermal effect, the design of a 1 x 2 ultrasonic-wave switch for the specific frequency of f = 1.64 MHz at room temperature has been reported. The thermal effects can be used to switch the phononic bandgap frequency. To the best of our knowledge, this is for the first time ever that a 1 x 2 ultrasonic switch has been proposed in two-dimensional solid/fluid phononic crystals.