Issue 40, 2023

Distinct anharmonic characteristics of phonon-driven lattice thermal conductivity and thermal expansion in bulk MoSe2 and WSe2

Abstract

Using inelastic neutron scattering and X-ray diffraction measurements, together with ab initio and machine-learning molecular dynamics simulations, we bring out the distinct nature of anharmonicity in the phonon spectra of MoSe2 and WSe2 relevant to thermal transport and thermal expansion behaviour. We show that the perturbation method, including 4th-order force constants, is insufficient to capture the temperature-dependent explicit anharmonicity. The Green–Kubo method captures the explicit anharmonicity and reproduces the thermal conductivity (κl) with high fidelity. Our mode-resolved calculation reveals that the major contribution (∼90%) to κl is attributed to a small explicit anharmonicity of low-energy phonons. In contrast, these modes exhibit large positive Grüneisen parameters (implicit anharmonicity), causing the large thermal expansion of the material.

Graphical abstract: Distinct anharmonic characteristics of phonon-driven lattice thermal conductivity and thermal expansion in bulk MoSe2 and WSe2

Supplementary files

Article information

Article type
Paper
Submitted
30 Jun 2023
Accepted
19 Sep 2023
First published
19 Sep 2023

J. Mater. Chem. A, 2023,11, 21864-21873

Distinct anharmonic characteristics of phonon-driven lattice thermal conductivity and thermal expansion in bulk MoSe2 and WSe2

M. K. Gupta, S. Kumar, R. Mittal, S. K. Mishra, S. Rols, O. Delaire, A. Thamizhavel, P. U. Sastry and S. L. Chaplot, J. Mater. Chem. A, 2023, 11, 21864 DOI: 10.1039/D3TA03830K

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