Ultra-low lattice thermal conductivity of monolayer penta-silicene and penta-germanene

文献情報

出版日 2019-10-30

DOI 10.1039/C9CP05246A

インパクトファクター 3.676

著者

Zhibin Gao, Zhaofu Zhang, Gang Liu, Jian-Sheng Wang

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要旨

We study the lattice thermal conductivity of two-dimensional (2D) pentagonal systems, such as penta-silicene and penta-germanene. Penta-silicene has been recently reported, while the stable penta-germanene, made up of another group IV element, is first revealed by our ab initio calculations. We find that both penta-silicene and penta-germanene at room temperature have ultra-low lattice thermal conductivities, κ, of 1.29 W m−1 K−1 and 0.30 W m−1 K−1, respectively. To the best of our knowledge, penta-germanene may have the lowest κ in 2D crystal materials. We attribute the ultra-low κ to the weak phonon harmonic interaction and strong anharmonic scattering. A small phonon group velocity, a small Debye frequency, a large Grüneisen parameter, and a large number of modes available for phonon–phonon interplay together lead to the ultra-low κ of penta-silicene and penta-germanene. These discoveries provide new insight into the manipulation of ultra-low κ in 2D materials and highlight the potential applications of silicon and germanium based high thermoelectric materials.

掲載誌

Physical Chemistry Chemical Physics

CiteScore: 5.5

自己引用率: 10.3%

年間論文数: 3036

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