Supervisor of Master's Candidates
E-Mail:b2d54cbcdf83626fc03140142e946ddd1498954acc2b2d116fda3e09a4333c9343ab48cf9edb524db1899fecbc7609c510186408ebd08a58757c9f64cb11de90cc21ea98b97b3b6b3aeaf5d2e4cc59675329d9878dc0f33bc5b54729544244062771e2cf3767605f15df0f0752cfe3a75ede22c6bbb27ce3531dab6eff08bdf0
School/Department:材料与物理学院
Education Level:With Certificate of Graduation for Doctorate Study
Business Address:南湖校区理科楼B522
Contact Information:Email: yifeng@cumt.edu.cn Phone: 15162129413
Degree:Doctor
Discipline:Physics
Paper Publications
Particlelike and wavelike behavior of phonons in Cs2AgIn𝑋6 (𝑋=Cl, Br) perovskites: How rattling vibrations and octahedral rotations govern thermal transport
Impact Factor:3.9
DOI number:10.1103/23m4-vt92
Affiliation of Author(s):材料与物理学院
Journal:Physical Review B
Place of Publication:American Physical Society
Funded by:国家自然科学基金面上项目(No. 12374079, 12174017)
Abstract:Conventional Peierls theory cannot fully capture the thermal transport in strongly anharmonic compounds (e.g., lead-free halide double perovskites) because it does not account for the significant wavelike behavior of phonons—a consequence of their inherent capability to interfere and tunnel. Here, we elucidate the mechanism behind the ultralow lattice thermal conductivity in model systems Cs2AgInCl6 and Cs2AgInBr6 through a combined evaluation of the particlelike and wavelike thermal transport channels. The rattling vibrations of Cs atoms suppress the particlelike channel through enhanced anharmonicity and promote the wavelike channel by flattening phonon branches to enhance coherence. Furthermore, the 𝑇1𝑔 rotational mode of the InX6 octahedron induces stronger quartic anharmonicity in Cs2AgInBr6 than in Cs2AgInCl6, which primarily enhances four-phonon scattering processes to further suppress the particlelike channel. In contrast, the wavelike contributions in both compounds remain comparable due to a compensating effect between the stronger coherent coupling in Cs2AgInBr6 and the larger group velocities in Cs2AgInCl6. Overall, the dominance of the wavelike channel is more pronounced in Cs2AgInBr6. Finally, the dominant wavelike contribution leads to a markedly weaker temperature dependence of the total thermal conductivity in both compounds, which is more notable in Cs2AgInBr6 with a scaling exponent of 𝑇−0.19 compared to 𝑇−0.52 in Cs2AgInCl6. Our work establishes the wavelike channel as a vital mechanism for thermal transport in lead-free halide double perovskites, providing novel insights into their fundamental thermal properties.
First Author:周冉
Indexed by:Journal paper
Correspondence Author:时洪亮,段益峰
Discipline:Natural Science
First-Level Discipline:Physics
Document Type:J
Volume:114
Issue:01
Page Number:014318
ISSN No.:2469-9950
Translation or Not:no
Date of Publication:2026-07-28
Included Journals:SCI
Links to published journals:https://journals.aps.org/prb/abstract/10.1103/23m4-vt92