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arXiv · 2510.24511

Anisotropic Hot Carrier Relaxation and Coherent Phonon Dynamics in Type-II Weyl Semimetal TaIrTe4

Zheng Zhu·Jingwen Wang·Hao Yu·Jialin Lu·Tianshu Lai·Peng Yu·Tianran Jiang·Ke Chen
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Abstract

The unique energy band and crystal structure of the layered type-II Weyl semimetal TaIrTe4 hold great promise for high-performance broadband anisotropic optoelectronic devices. Therefore, gaining an in-depth understanding of the interactions between internal microscopic particles is of vital importance. Here, we employ a two-color pump-probe system to reveal the anisotropic electron-phonon coupling (EPC) and coherent phonon dynamics in bulk TaIrTe4. The carrier relaxation exhibits a four-exponential decay process, with strong dependence on polarization of probe pulse, indicating that EPC strength is closely related to the crystal axes (a/b-axes). In addition, we observe three coherent phonon modes in bulk TaIrTe4: 38.5 GHz, 0.44 THz and 1.29 THz. Their oscillation amplitudes and dephasing times also show anisotropic responses to the probe polarization. We also investigate the in-plane cross-directional thermal conductivity coefficient of TaIrTe4 by beam-offset frequency-domain thermal reflection (FDTR). The thermal conductivity coefficient along the a-axis and b-axis directions are ka=14.4 W/mK and kb=3.8 W/mK, respectively. This represents a significant in-plane anisotropy. Our work not only reveals the key role of anisotropic EPC in controlling the thermal and optical properties of TaIrTe4, but also provides insights into designing polarization-sensitive optoelectronic devices based on topological semimetals.

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Zheng Zhu, Jingwen Wang, Hao Yu, Jialin Lu, Tianshu Lai, Peng Yu, Tianran Jiang, Ke Chen. 2025-10-28. Anisotropic Hot Carrier Relaxation and Coherent Phonon Dynamics in Type-II Weyl Semimetal TaIrTe4. https://arxiv.org/abs/2510.24511

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