Large Transverse Thermopower in Shape-Engineered Tilted Leg Thermopile

Abstract

We demonstrate that a novel device design, where a shape-engineered tilted-leg thermopile structure is employed, significantly enhances the output voltage in the transverse direction. Owing to the shape engineering of the leg geometry, an additional temperature gradient develops along the long direction of the leg, which is perpendicular to the direction of the applied temperature gradient, thereby generating an additional Seebeck voltage V_SE that adds to the Anomalous Nernst effect (ANE) voltage V_ANE. We further show that a simple adjustment of electrode position within the device can further increase V_SE. The tilted leg device with electrode adjustment demonstrates a 990% enhanced transverse output voltage compared to that of conventional rectangular leg thermopile-structured devices, wherein only the ANE occurs. This combined output voltage from both the Seebeck effect and ANE is equivalent to the value that surpasses the state-of-the-art ANE materials and devices currently available. The numerical analysis shows the tendencies of the electrical and thermal outputs of the tilted-leg device, which guides a way to further improve the output voltage. Our study paves the way to develop highly efficient transverse TE devices that can overcome intrinsic materials challenges by utilizing the degree of freedom of device design.