Suppression of intervalley scattering and enhanced phonon anharmonic interactions in 2D Bi2TeSe2: Crystal-field symmetry and band convergence

Lei Peng; Ao Wu; Yujie Xia; Haotian Zhang; Yuting Yang; Hezhu Shao; Ying Chen; Juan Zhang; Le Shu; Heyuan Zhu; Yuxiang Zheng; Hao Zhang

Journal of Materiomics (Mar 2024)

Suppression of intervalley scattering and enhanced phonon anharmonic interactions in 2D Bi2TeSe2: Crystal-field symmetry and band convergence

Lei Peng,
Ao Wu,
Yujie Xia,
Haotian Zhang,
Yuting Yang,
Hezhu Shao,
Ying Chen,
Juan Zhang,
Le Shu,
Heyuan Zhu,
Yuxiang Zheng,
Hao Zhang

Affiliations

Lei Peng: School of Information Science and Technology, Department of Optical Science and Engineering, Fudan University, Shanghai 200433, China
Ao Wu: School of Information Science and Technology, Department of Optical Science and Engineering, Fudan University, Shanghai 200433, China
Yujie Xia: School of Information Science and Technology, Department of Optical Science and Engineering, Fudan University, Shanghai 200433, China
Haotian Zhang: School of Information Science and Technology, Department of Optical Science and Engineering, Fudan University, Shanghai 200433, China
Yuting Yang: School of Information Science and Technology, Department of Optical Science and Engineering, Fudan University, Shanghai 200433, China
Hezhu Shao: College of Electrical and Electronic Engineering, Wenzhou University, Wenzhou 325035, China
Ying Chen: Department of Light Sources and Illuminating Engineering, Fudan University, Shanghai 200433, China
Juan Zhang: School of Information Science and Technology, Department of Optical Science and Engineering, Fudan University, Shanghai 200433, China
Le Shu: School of Information Science and Technology, Department of Optical Science and Engineering, Fudan University, Shanghai 200433, China
Heyuan Zhu: School of Information Science and Technology, Department of Optical Science and Engineering, Fudan University, Shanghai 200433, China
Yuxiang Zheng: School of Information Science and Technology, Department of Optical Science and Engineering, Fudan University, Shanghai 200433, China; Yiwu Research Institute of Fudan University, Yiwu 322000, China; Corresponding author. School of Information Science and Technology, Department of Optical Science and Engineering, Fudan University, Shanghai 200433, China.
Hao Zhang: School of Information Science and Technology, Department of Optical Science and Engineering, Fudan University, Shanghai 200433, China; Yiwu Research Institute of Fudan University, Yiwu 322000, China; Corresponding author. School of Information Science and Technology, Department of Optical Science and Engineering, Fudan University, Shanghai 200433, China.

Journal volume & issue: Vol. 10, no. 2
pp. 386 – 395

Abstract

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The electron-phonon (el-ph) and phonon-phonon interactions play a key role in determining electronic and thermal transport properties, respectively, in promising two-dimensional (2D) semiconductor devices. In this study, we investigated el-ph interactions using Wannier-Fourier interpolation method and renormalized phonon scattering considering finite-temperature effects in Bi2TeSe2 monolayer. The results show that the optical phonon modes dominate the carrier scattering, where level repulsion induced by crystal field splitting and spin-orbit coupling (SOC) effect effectively suppresses intervalley scattering, leading to high hole mobility. Moreover, the strong anharmonicity in Bi2TeSe2 monolayer results in the temperature-dependent softening of its optical phonons, along with a corresponding variation in interatomic force constants (IFCs). As a result, the lattice thermal conductivity is remarkably low and exhibits weak temperature dependence. Finally, the predicted dimensionless thermoelectric figure of merit exceeds unity in the range of 200–800 K, indicating the potential of Bi2TeSe2 monolayer for thermoelectric applications. This work provides new insights into the elimination of intervalley scattering by crystal field splitting and SOC effects, and paves the way for the evaluation of thermoelectric properties of materials with complex scattering mechanisms and strong anharmonicity.

Published in Journal of Materiomics

ISSN: 2352-8478 (Print); 2352-8486 (Online)
Publisher: Elsevier
Country of publisher: Netherlands
LCC subjects: Technology: Electrical engineering. Electronics. Nuclear engineering: Materials of engineering and construction. Mechanics of materials
Website: https://www.sciencedirect.com/journal/journal-of-materiomics

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