Particlelike Phonon Propagation Dominates Ultralow Lattice Thermal Conductivity in Crystalline ${\mathrm{Tl}}_3{\mathrm{VSe}}_4$

Journal Article · 14 February 2020 · Physical Review Letters

DOI: https://doi.org/10.1103/PhysRevLett.124.065901 · OSTI ID:1600480

Xia, Yi  ^[1]; Pal, Koushik  ^[1]; He, Jiangang ^[1]; Ozoliņš, Vidvuds ^[2]; Wolverton, Chris ^[1]

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1. Northwestern Univ., Evanston, IL (United States)
2. Yale Univ., New Haven, CT (United States)

We explore the microscopic mechanisms of ultralow lattice thermal conductivity ($$\kappa_{l}$$) in Tl$$_{3}$$VSe$$_{4}$$~by combining a first-principles density-functional theory (DFT) based framework of anharmonic lattice dynamics with the Peierls-Boltzmann transport equation (PBTE) for phonons. We include contributions of the three- and four-phonon scattering processes to the phonon lifetimes as well as the temperature-dependent anharmonic renormalization of phonon energies arising from an unusually strong quartic anharmonicity in Tl$$_{3}$$VSe$$_{4}$$. In contrast to a recent report by Mukhopadhyay~\etal [\textcolor{blue}{Science 360, 1455 (2018)}] which suggested that a significant contribution to $$\kappa_{l}$$ arises from random walks among uncorrelated oscillators, we show that particle-like propagation of phonon excitations can successfully explain the experimentally observed ultralow $$\kappa_{l}$$. Our results are also supported by explicit calculations of the off-diagonal terms of the heat-current operator, which are found to be small and indicate that wave-like tunneling of heat-carrying vibrations is of minor importance. Our results (i) resolve the discrepancy between the theoretical and experimental $$\kappa_{l}$$, (ii) offer new insights into the minimum $$\kappa_{l}$$ achievable in \TlVSe, and (iii) highlight the importance of high-order anharmonicity in low-$$\kappa_{l}$$ systems. The methodology demonstrated here may be used to resolve the discrepancies between the experimentally measured and the theoretically calculated $$\kappa_{l}$$ in skutterides and perovskites, as well as to understand the glasslike $$\kappa_{l}$$ in complex crystals with strong anharmonicity, leading towards the goal of rational design of new materials.

• Research Organization: Northwestern Univ., Evanston, IL (United States); University of California, Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES); National Science Foundation (NSF)
• Grant/Contract Number: SC0014520; AC02-05CH11231; DMR-1611507
• OSTI ID: 1600480
• Alternate ID(s): OSTI ID: 1599684; OSTI ID: 1778883
• Journal Information: Physical Review Letters, Vol. 124, Issue 6; ISSN 0031-9007
• Publisher: American Physical Society (APS)Copyright Statement
• Country of Publication: United States
• Language: English