article published yes Niuchang Ouyang author Zezhu Zeng author 54a2c730-803f-11ed-ab7e-95b29d2680e7 Chen Wang author Qi Wang author Yue Chen author BiCh department IST-BRIDGE: International postdoctoral program project The phonon transport mechanisms and ultralow lattice thermal conductivities (κL) in silver halide AgX (X=Cl,Br,I) compounds are not yet well understood. Herein, we study the lattice dynamics and thermal property of AgX under the framework of perturbation theory and the two-channel Wigner thermal transport model based on accurate machine learning potentials. We find that an accurate extraction of the third-order atomic force constants from largely displaced configurations is significant for the calculation of the κL of AgX, and the coherence thermal transport is also non-negligible. In AgI, however, the calculated κL still considerably overestimates the experimental values even including four-phonon scatterings. Molecular dynamics (MD) simulations using machine learning potential suggest an important role of the higher-than-fourth-order lattice anharmonicity in the low-frequency phonon linewidths of AgI at room temperature, which can be related to the simultaneous restrictions of the three- and four-phonon phase spaces. The κL of AgI calculated using MD phonon lifetimes including full-order lattice anharmonicity shows a better agreement with experiments. American Physical Society2023 eng 2469-9950 2469-9969 00110115250000110.1103/PhysRevB.108.174302 10817 Ouyang, N., Zeng, Z., Wang, C., Wang, Q., &#38; Chen, Y. (2023). Role of high-order lattice anharmonicity in the phonon thermal transport of silver halide AgX (X=Cl,Br, I). <i>Physical Review B</i>. American Physical Society. <a href="https://doi.org/10.1103/PhysRevB.108.174302">https://doi.org/10.1103/PhysRevB.108.174302</a> N. Ouyang, Z. Zeng, C. Wang, Q. Wang, Y. Chen, Physical Review B 108 (2023). Ouyang N, Zeng Z, Wang C, Wang Q, Chen Y. Role of high-order lattice anharmonicity in the phonon thermal transport of silver halide AgX (X=Cl,Br, I). <i>Physical Review B</i>. 2023;108(17). doi:<a href="https://doi.org/10.1103/PhysRevB.108.174302">10.1103/PhysRevB.108.174302</a> Ouyang, Niuchang, et al. “Role of High-Order Lattice Anharmonicity in the Phonon Thermal Transport of Silver Halide AgX (X=Cl,Br, I).” <i>Physical Review B</i>, vol. 108, no. 17, 174302, American Physical Society, 2023, doi:<a href="https://doi.org/10.1103/PhysRevB.108.174302">10.1103/PhysRevB.108.174302</a>. N. Ouyang, Z. Zeng, C. Wang, Q. Wang, and Y. Chen, “Role of high-order lattice anharmonicity in the phonon thermal transport of silver halide AgX (X=Cl,Br, I),” <i>Physical Review B</i>, vol. 108, no. 17. American Physical Society, 2023. Ouyang N, Zeng Z, Wang C, Wang Q, Chen Y. 2023. Role of high-order lattice anharmonicity in the phonon thermal transport of silver halide AgX (X=Cl,Br, I). Physical Review B. 108(17), 174302. Ouyang, Niuchang, Zezhu Zeng, Chen Wang, Qi Wang, and Yue Chen. “Role of High-Order Lattice Anharmonicity in the Phonon Thermal Transport of Silver Halide AgX (X=Cl,Br, I).” <i>Physical Review B</i>. American Physical Society, 2023. <a href="https://doi.org/10.1103/PhysRevB.108.174302">https://doi.org/10.1103/PhysRevB.108.174302</a>. 146052023-11-26T23:00:54Z2025-09-09T13:31:19Z