Chen Yongjin, Zhang Bin, Zhang Yongsheng, Wu Hong, Peng Kunling, Yang Hengquan, Zhang Qing, Liu Xiaopeng, Chai Yisheng, Lu Xu, Wang Guoyu, Zhang Ze, He Jian, Han Xiaodong, Zhou Xiaoyuan
College of Physics and Center for Quantum Materials and Devices Institute of Advanced Interdisciplinary Studies Chongqing University Chongqing 401331 P. R. China.
Beijing Key Laboratory and Institute of Microstructure and Property of Advanced Materials Beijing University of Technology Beijing 100124 P. R. China.
Adv Sci (Weinh). 2021 Feb 8;8(8):2002051. doi: 10.1002/advs.202002051. eCollection 2021 Apr.
It remains a daunting task to quantify the configurational entropy of a material from atom-revolved electron microscopy images and correlate the results with the material's lattice thermal conductivity, which strides across statics, dynamics, and thermal transport of crystal lattice over orders of magnitudes in length and time. Here, a proof-of-principle study of atomic-scale visualization and quantification of configurational entropy in relation to thermal conductivity in single crystalline trigonal GeSbTe (aka -GeSbTe) with native atomic site disorder is reported. A concerted effort of large -GeSbTe single crystal growth, in-lab developed analysis procedure of atomic column intensity, the visualization and quantification of configurational entropy including corresponding modulation, and thermal transport measurements enable an entropic "bottom-up" perspective to the lattice thermal conductivity of -GeSbTe. It is uncovered that the configurational entropy increases phonon scattering and reduces phonon mean free path as well as promotes anharmonicity, thereby giving rise to low lattice thermal conductivity and promising thermoelectric performance. The current study sheds lights on an atomic scale bottom-up configurational entropy design in diverse regimes of structural and functional materials research and applications.
从原子分辨率电子显微镜图像中量化材料的构型熵，并将结果与材料的晶格热导率相关联，仍然是一项艰巨的任务，晶格热导率跨越了晶格在长度和时间上多个数量级的静态、动态和热输运。在此，报道了一项关于具有天然原子位点无序的单晶三角相GeSbTe（即β-GeSbTe）中与热导率相关的构型熵的原子尺度可视化和量化的原理验证研究。通过协同努力实现了大尺寸β-GeSbTe单晶生长、实验室开发的原子列强度分析程序、构型熵的可视化和量化（包括相应的调制）以及热输运测量，从而为β-GeSbTe的晶格热导率提供了一种基于熵的“自下而上”的视角。研究发现，构型熵增加了声子散射，减小了声子平均自由程，并促进了非谐性，从而导致低晶格热导率和有前景的热电性能。当前的研究为结构和功能材料研究及应用的不同领域中的原子尺度自下而上的构型熵设计提供了启示
