Unusual anisotropic thermal expansion in multilayer SnSe leads to positive-to-negative crossover of Poisson’s ratio

ORAL

Abstract

An unusual anisotropic thermal expansion occurs in monolayer SnSe when it is subjected to heating, i.e., the long lattice constant contracts, and the short one expands, causing a rectangular-to-square-lattice phase transition at a critical temperature (Tc). An even more prominent monolayer-to-bulk thermal-expansion behavior has been discovered by density-functional-theory calculations combined with Grüneisen’s theory within the quasiharmonic approximation[1]. The unusual thermal expansion survives in multilayer SnSe, while the thermal expansion coefficients of different layers are almost unchanged. This phenomenon can be explained by a delicate balance between the elastic stiffness coefficient and Grüneisen parameters. Finally, the Poisson’s ratio of multilayer SnSe decreases at elevated temperatures and turns negative, indicating a crossover point of diminished Poisson’s ratio at some intermediate temperature. These findings provide not only new understanding of the thermal properties of monochalcogenides, but also a feasible approach to design zero-Poisson’s-ratio materials.

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Presenters

  • Yu-Tian Zhang

    • School of physical sciences, Institute of Physics and University of Chinese Academy of Sciences

Authors

  • Yu-Tian Zhang

    • School of physical sciences, Institute of Physics and University of Chinese Academy of Sciences

  • Rui-Zi Zhang

    • School of physical sciences, Institute of Physics and University of Chinese Academy of Sciences

  • Jian Liu

    • Optics and Thermal Radiation Research Center, Shandong University

  • Yu-Yang Zhang

    • Chinese Academy of Sciences,Institute of Physics
    • University of Chinese Academy of Sciences
    • Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
    • School of physical sciences, Institute of Physics and University of Chinese Academy of Sciences
    • Institute of Physics, Chinese Academy of Sciences
    • Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences

  • Shixuan Du

    • Chinese Academy of Sciences,Institute of Physics
    • Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
    • School of physical sciences, Institute of Physics and University of Chinese Academy of Sciences
    • Institute of Physics, Chinese Academy of Sciences
    • Chinese Academy of Science
    • Chinese Academy of Sciences, Institute of Physics
    • Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences

  • Sokrates T Pantelides

    • Department of Physics and Engineering, Vanderbilt University
    • Department of Physics and Astronomy, Vanderbilt Univ
    • Department of Physics and Astronomy, Vanderbilt University
    • Vanderbilt Univ
    • Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235, USA
    • Institute of Physics, Chinese Academy of Sciences
    • Department of Physics and Astronomy & Department of Electrical Engineering and Computer Science, Vanderbilt University
    • Department of Physics and Astronomy and Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN
    • Department of Electrical Engineering and Computer Science, Vanderbilt University
    • Department of Physics and Astronomy and Department of Electrical Engineering and Computer Science, Vanderbilt University
    • Vanderbilt University