Anisotropic thermal expansion and thermodynamic properties of monolayer beta-Te

Article

关键词: INITIO MOLECULAR-DYNAMICS;    TOTAL-ENERGY CALCULATIONS;    GROWTH;    1ST-PRINCIPLES;    SEMICONDUCTOR;    LAYERS;   

DOI  :  10.1103/PhysRevB.99.195436

来源: SCIE

【 摘 要 】

Recently, beta-Te [atomically two-dimensional (2D) tellurium] with rectangular crystal structure has been synthesized successfully on highly oriented pyrolytic graphite substrates by using molecular beam epitaxy [Z. Zhu et al., Phys. Rev. Lett. 119, 106101 (2017); Chen et al., Nanoscale 9, 15945 (2017)]. It has been found to possess remarkable properties such as ultralow lattice thermal conductivity and high thermoelectric efficiency. Based on first-principles calculations, we study the thermal expansion and thermodynamic properties of the experimental phase monolayer beta-Te, using the quasiharmonic approach. It is found that beta-Te shows large positive thermal expansion at elevated temperature, while the linear thermal expansion coefficient is negative along the a direction at very low temperature. The linear thermal expansion coefficient along the b direction is 4.9 x 10(-5) K-1 at 500 K, which is considerably large in 2D materials. beta-Te exhibits strong in-plane anisotropy, including thermal expansion, 2D elastic moduli, and Poisson's ratios. However, the elastic moduli, Poisson's ratios and the in-plane anisotropy are weakened with increasing temperature, and the variations are dominated by the generalized mode Gruneisen parameters.

【 授权许可】

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