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arXiv · 2506.21479

Synergy of Rashba and Topological Effects for High-Performance Bismuth-Based Thermoelectrics

Lei Peng·Ruixiao Lian·Hongyu Chen·Ben Li·Yu Wu·Yuxiang Zheng·Hao Zhang
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Abstract

Band convergence is a key strategy for enhancing thermoelectric (TE) performance. Herein, we demonstrate a promising approach to enhance band convergence through inducing Rashba splitting in topological insulators. Theoretically designed Janus $\beta$-Bi$_2$Se$_2$Te and $\beta$-Bi$_2$Te$_2$Se exhibited inherent topological band inversion and Rashba splitting due to the strong spin-orbit coupling (SOC) with broken inversion symmetry. These characteristics synergistically improve band convergence, leading to a substantially enhanced power factor. Meanwhile, the Janus structural asymmetry suppresses lattice thermal conductivity. Consequently, Janus structures achieve boosted TE performance, especially for $\beta$-Bi$_2$Se$_2$Te, peaking figure of merit ($zT$) of 2.82. This work establishes a new framework for designing Janus topological compounds with high TE performance by the synergistic effect of Rashba splitting and band inversion.

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Lei Peng, Ruixiao Lian, Hongyu Chen, Ben Li, Yu Wu, Yuxiang Zheng, Hao Zhang. 2025-06-26. Synergy of Rashba and Topological Effects for High-Performance Bismuth-Based Thermoelectrics. https://arxiv.org/abs/2506.21479

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