Thermopower generation and thermoelectric cooling in a Kane-Mele normal-insulator-superconductor nano-junction

Abstract: We have studied thermoelectric effect of a Kane-Mele normal-insulator-superconductor (KMNIS) junction at ultra-low temperatures using a modified version of the well-known Blonder-Tinkham-Klapwijk (BTK) theory. Since both the (electronic) charge and thermal current due to the carriers are sensitive to the strengths of the spin-orbit coupling (SOC) present in the Kane-Mele model, a tunability of this junction device with regard to its thermoelectric properties can be experimentally achieved by certain techniques that are used to manipulate the values of the spin-orbit couplings. We have computed the Seebeck coefficient, the Figure of Merit, the thermoelectric cooling, the coefficient of performance of the KMNIS junction as a self-cooling device and investigated the role of the Rashba SOC (RSOC) and intrinsic SOC (ISOC) parameters therein. Our results on the thermoelectric cooling indicate practical realizability and usefulness for efficient cooling detectors, sensors, and quantum devices and hence could be crucial to experimental success of the thermoelectric applications of such junction devices. Further we have briefly touched upon the condition that distinguishes transmission through a topological insulator from an ordinary one.