Strong low-energy rattling modes enabled liquid-like ultralow thermal conductivity in a well-ordered solid  

作　　者：Peng-Fei Liu Xiyang Li Jingyu Li Jianbo Zhu Zhen Tong Maiko Kofu Masami Nirei Juping Xu Wen Yin Fangwei Wang Tianjiao Liang Lin Xie Yongsheng Zhang David J.Singh Jie Ma Hua Lin Junrong Zhang Jiaqing He Bao-Tian Wang 

机构地区：[1]Institute of High Energy Physics,Chinese Academy of Sciences,Beijing 100049,China [2]Spallation Neutron Source Science Center,Dongguan 523803,China [3]Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100080,China [4]Department of Physics&Astronomy and Stewart Blusson Quantum Matter Institute,University of British Columbia,Vancouver V6T 1Z4,Canada [5]State Key Laboratory of Advanced Welding and Joining Harbin Institute of Technology,Harbin 150001,China [6]School of Advanced Energy,Sun Yat-Sen University,Shenzhen 518107,China [7]J-PARC Center,Japan Atomic Energy Agency,Tokai,Ibaraki 319-1195,Japan [8]Shenzhen Key Laboratory of Thermoelectric Materials,Department of Physics,Southern University of Science and Technology,Shenzhen 518055,China [9]Guangdong Provincial Key Laboratory of Advanced Thermoelectric Materials and Device Physics,Southern University of Science and Technology,Shenzhen 518055,China [10]Advanced Research Institute of Multidisciplinary Sciences,Qufu Normal University,Qufu 273165,China [11]Department of Physics and Astronomy,University of Missouri,Columbia,65211,USA [12]Key Laboratory of Artificial Structures and Quantum Control,School of Physics and Astronomy,Shanghai Jiao Tong University,Shanghai 200240,China [13]State Key Laboratory of Structural Chemistry,Fujian Institute of Research on the Structure of Matter,Chinese Academy of Sciences,Fuzhou 350002,China

出　　处：《National Science Review》2024年第12期106-115,共10页国家科学评论(英文版)

基　　金：supported by the National Natural Science Foundation of China(12074381,12104458,U2330104,12005230 and 52106068);Guangdong Basic and Applied Basic Research Foundation(2022A1515140030,2023A1515111190 and 2024A1515010484);Outstanding Talents Training Fund in Shenzhen(202108).

摘　　要：Crystalline solids exhibiting inherently low lattice thermal conductivity(κL)are of great importance in applications such as thermoelectrics and thermal barrier coatings.However,κL cannot be arbitrarily low and is limited by the minimum thermal conductivity related to phonon dispersions.In this work,we report the liquid-like thermal transport in a well-ordered crystalline CsAg_(5)Te_(3),which exhibits an extremely lowκL value of∼0.18 Wm^(−1)K^(−1).On the basis of first-principles calculations and inelastic neutron scattering measurements,we find that there are lots of low-lying optical phonon modes at∼3.1 meV hosting the avoided-crossing behav ior w ith acoustic phonons.These strongly localized modes are accompanied by weakly bound rattling Ag atoms with thermally induced large amplitudes of vibrations.Using the two-channel model,we demonstrate that coupling of the particle-like phonon modes and the heat-carrying wave-like phonons is essential for understanding the lowκ_(L),which is heavily deviated from the 1/T temperature dependence of the standard Peierls theory.In addition,our analysis indicates that the soft structural framework with liquid-like motions of the fluctuating Ag atoms is the underlying cause that leads to the suppression of the heat conduction in CsAg5 Te3.These factors synergistically account for the ultralowκL value.Our results demonstrate that the liquid-like heat transfer could indeed exist in a well-ordered crystal.

关 键 词：thermal conductivity THERMOELECTRIC phonon dynamic inelastic neutron scattering 

分 类 号：O551[理学—热学与物质分子运动论]