On the physical foundations of topological thermoelectricity and its improvement

Thermoelectricity has extraordinary scientific and technological interest due to its ability to utilize heat losses through the Seebeck effect and Peltier cooling in circuits. However, the efficiency of thermoelectric materials remains relatively low, making them economically viable in fewer cases than desired. A promising possibility lies in the best thermoelectric materials at room temperature, specifically the well-known tetradymite-type structures, primarily compounds based on Bi 2 Te 3 . These materials are characterized as topological insulators, allowing for the introduction of new physical perspectives. Therefore, it is reasonable to closely investigate the interplay between topology and thermoelectricity in these systems, with the aim of elucidating the underlying physical mechanisms. We show that, near the surface–bulk interface, the electrodynamics of axions coupled to massless fermions, Thouless pump currents, the chiral anomaly, and topological mass are intimately interconnected in a way that enables the mutual conversion of heat and electrical energy. That gives rise to a thermoelectric effect whose efficiency can be enhanced by integer multiples. We extend this study to heterostructures of topological insulators and topological superconductors. These phases are topologically complementary and may use the proximity effect to share topological quantum numbers. This offers a pathway to enhance topological thermoelectricity.