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arXiv · 2508.20969

Gate-tunable nonreciprocal thermoelectric effects on the surface states of topological insulators

Phillip Mercebach·Sun-Yong Hwang·Bo Lu·Björn Sothmann·Yukio Tanaka·Pablo Burset
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Abstract

Thermoelectric devices at the nanoscale offer promising routes for on-chip refrigeration and waste-heat recovery, yet most semiconductor-based implementations suffer from limited tunability and narrow operational ranges. We introduce a highly flexible thermoelectric platform based on a ballistic junction formed by two gate-tunable regions of a topological insulator surface state bridged by a magnetic barrier. We theoretically demonstrate that such device exhibits strong electrical control over both refrigeration and thermoelectric power generation via side gates. We exploit the interplay between strong spin-orbit coupling and magnetism to achieve pronounced nonreciprocal transport, asymmetric cooling and tunable diode-like behavior. To demonstrate experimental feasibility, we further analyze refrigeration efficiency and phonon-limited performance in realistic material settings.

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Phillip Mercebach, Sun-Yong Hwang, Bo Lu, Björn Sothmann, Yukio Tanaka, Pablo Burset. 2025-08-28. Gate-tunable nonreciprocal thermoelectric effects on the surface states of topological insulators. https://arxiv.org/abs/2508.20969

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