Semiconductor Materials - 03

Abstract

The electrocaloric effect is the most widely recognized thermal phenomenon in dielectrics, arising from changes in an applied electric field that lead to heat absorption or release throughout the system due to entropy changes associated with dielectric polarization. In contrast, thermoelectric effects, which simultaneously generate both heating and cooling within a material, have received limited attention in dielectrics, primarily because of their insulating nature. Nevertheless, by analogy with the transport phenomena associated with magnetization dynamics in magnetic materials [1], it is conceivable that thermoelectric effects might arise from polarization dynamics in dielectrics [2]. In this study, we systematically and precisely examined the thermal responses induced by electric fields in dielectrics. We employed lock-in thermography, a technique that combines infrared imaging with Fourier analysis, enabling spatial mapping of both the magnitude and phase of heat responses synchronized to the input signal. This method has revealed not only the electrocaloric effect [3] (Fig.1) and novel thermoelectric responses at ac frequencies.