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arXiv · 2307.04278

Phononic transport in 1T prime-MoTe2: anisotropic structure with an isotropic lattice thermal conductivity

Xiangyue Cui·Xuefei Yan·Bowen Wang·Yongqing Cai
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Abstract

Molybdenum ditelluride (MoTe2) is an unique transition metal dichalcogenide owing to its energetically comparable 1H and 1T prime phases. This implies a high chance of coexistence of 1H-1T prime heterostructures which poses great complexity in the measurement of the intrinsic lattice thermal conductivities (kappa). In this work, via first-principles calculations, we examine the lattice-wave propagation and thermal conduction in this highly structurally anisotropic 1T prime MoTe2. Our calculation shows that the 1T prime phase has a sound velocity of 2.13 km/s (longitudinal acoustic wave), much lower than that of the 1H phase (4.05 km /s), indicating a staggered transmission of lattice waves across the boundary from 1H to 1T prime phase. Interestingly, the highly anisotropic 1T prime MoTe2 shows nearly isotropic and limited kappa_L of 13.02 W/mK, owing to a large Gruneisen parameter of acoustic flexural mode, heavy masses of Mo and Te elements and a low phonon group velocity. Accumulative kappa_L as a function of mean free path (MFP) indicates phonons with MFP less than ~300 nm contribute 80% of kappa_L and an inflection point at ~600 nm. Our results will be critical for understanding of the size dependent kappa_L of nanostructured 1T prime MoTe2.

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Xiangyue Cui, Xuefei Yan, Bowen Wang, Yongqing Cai. 2023-07-09. Phononic transport in 1T prime-MoTe2: anisotropic structure with an isotropic lattice thermal conductivity. https://doi.org/10.1016/j.apsusc.2022.155238

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