Sponsor
S.S. gratefully acknowledges financial support received from IIT Kanpur through an institutional fellowship. Y.X. acknowledges support from the US National Science Foundation through awards DMR-2317008 and CBET- 2445361. K.P. thanks (i) IIT Kanpur for financial support through an Initiation Grant and (ii) the Anusandhan National Research Foundation for the PAIR grant (ANRF/PAIR/2025/000002/PAIR-B). We also acknowledge the use of computational resources provided by the HPC2013 cluster and the Param Sanganak supercomputing facility at IIT Kanpur.
Published In
Physical Review B
Document Type
Pre-Print
Publication Date
12-12-2025
Subjects
Thermal Conductivity, Ordered crystalline compounds
Abstract
Ordered crystalline compounds exhibiting ultralow and glass-like thermal conductivity are both fundamentally and technologically important, where phonon quasi-particles dominate their heat transport. Understanding the microscopic mechanisms that govern such unusual transport behavior is necessary to unravel the complex interplay of crystal structure, phonons, and collective excitations of these quasi-particles. Here, we use state-of-the-art first-principles calculations based on quantum density functional theory to investigate the origin of experimentally measured unusually low and glassy thermal conductivity in semiconducting TlAgTe that possesses disconnected chains of Tl atoms within its three-dimensional crystalline framework made up of distorted AgTe4 tetrahedra. Utilizing a unifying framework of anharmonic lattice dynamics theory that combine phonon self-energy induced frequency renormalization, particle-like Peierls (κPl ) and wave-like coherent (κCl ) thermal transport contributions including three and four-phonon scattering channels, we successfully explain the experimental results both in terms of magnitude and temperature dependence. Our analysis reveals that TlAgTe exhibits several localized phonon modes arising from concerted rattling-like vibration of Tl atoms, which show strong temperature dependence and enhanced four-phonon scattering rates that are dominated by Umklapp processes, suppressing κPl to ultralow values. The ensuing strong anharmonicity induced by local structural distortions, lone-pair electrons, and rattling-like vibrations of the heavy cations lead to a transition from particle-like behavior to wave-like tunneling characteristics of the phonon modes above 40 cm−1, contributing significantly to κCl which increases with temperature. Our analysis uncovers important structureproperty relationship, which may be used in designing of novel materials with tunable thermal conductivity.
Rights
© Copyright the author(s) 2025
DOI
10.1103/q9ww-ls39
Persistent Identifier
https://archives.pdx.edu/ds/psu/44395
Publisher
American Physical Society (APS)
Citation Details
Published as: Semwal, S., Xia, Y., Wolverton, C., & Pal, K. (2025). Concerted rattling-induced strong anharmonicity and phonon coherence lead to ultralow glasslike thermal conductivity in TlAgTe. Physical Review B, 112(21).
Description
This is the author’s version of a work that was accepted for publication. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published as: Concerted rattling-induced strong anharmonicity and phonon coherence lead to ultralow glasslike thermal conductivity in TlAgTe. Physical Review B, 112(21).