Observation of the amplified transverse thermoelectric signals by reduced-dimensionality transport anisotropy.

Wang, Honghui; He, Bin; Feng, Xiaolong; Hu, Haihua; Koban, Ralf; Schnelle, Walter; Cheng, Erjian; Pan, Yu et al. · Nat Commun · 2026

basic_science · Level V

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Abstract

Transverse thermoelectric devices offer simplified geometries with flexible designs for next-generation cryogenic technologies. However, mechanisms on geometrical amplification of transverse thermoelectric effects remain elusive. Here we establish a general framework linking reduced dimensionality with its geometrical anisotropy to enhanced transverse thermoelectric responses. Taking quasi-one-dimensional Li<sub>0.9</sub>Mo<sub>6</sub>O<sub>17</sub> as a model platform, we combine theoretical modeling with systematic experiments to reveal extraordinarily large Nernst and Ettingshausen signals, reaching 11,430 μV/K (25 K, 9 T) and 0.0063 K · m/A (43.1 K, 9 T), respectively, together with a high power factor of 814 μW cm<sup>-1</sup> K<sup>-2</sup> at 25 K and 9 T. Dimensional reduction amplifies the Seebeck-driven electric field and enhances the reduced mobility through anisotropic Fermi surface geometry. These effects yield the transverse thermoelectric response far exceeding those of higher-dimensional systems with even ultrahigh carrier mobilities. Our findings highlight enhanced geometrical anisotropy as a powerful principle of design for engineering high-performance transverse thermoelectric systems.