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arXiv · 2207.13687

p x n-Type Transverse Thermoelectrics in a Type-II Weyl Semimetal TaIrTe4

Josh Mutch·Wei-Chih Chen·Cheng-Yi Huang·Paul Malinowski·Cheng-Chien Chen·Jiun-Haw Chu
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Abstract

p x n-type materials refer to materials with a p-type Seebeck coefficient in one direction and a n-type coefficient in the orthogonal direction. This type of materials allows for a transverse thermoelectric response, which is highly desirable for energy applications. Here, we report the observation of p x n-type behavior in TaIrTe4, a type-II Weyl semimetal, with an in-plane thermopower anisotropy S$_{xx}$-S$_{yy}$ reaches a maximum value 40${\mu}$V/K at 200K. Intriguingly. we found that such a p x n-type behavior is absent in the similar compound NbIrTe4. The presence and absence of p x n-type behavior in these two materials are consistent with density functional theory calculations, which further predict that the thermopower anisotropy in both compounds can be enhanced up to 130${\mu}$V/K by electron doping. Such a strong thermopower anisotropy originates from the presence of both p-type and n-type carriers, each with high mobility in one direction. These results suggest that although type-II Weyl semimetal phase does not guarantee the existence of p x n-type behavior, its unique band structure provides the ingredient to engineer and optimize this phenomenon.

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Josh Mutch, Wei-Chih Chen, Cheng-Yi Huang, Paul Malinowski, Cheng-Chien Chen, Jiun-Haw Chu. 2022-07-27. p x n-Type Transverse Thermoelectrics in a Type-II Weyl Semimetal TaIrTe4. https://arxiv.org/abs/2207.13687

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