Wu C Y, Sun L, Han J C, Gong H R
State Key Laboratory of Powder Metallurgy, Central South University Changsha Hunan 410083 China
Department of Educational Science, Hunan First Normal University Changsha Hunan 410205 China.
RSC Adv. 2019 Dec 9;9(69):40670-40680. doi: 10.1039/c9ra08341c. eCollection 2019 Dec 3.
First-principles calculations and Boltzmann transport theory have been combined to comparatively investigate the band structure, phonon spectrum, lattice thermal conductivity, electronic transport properties, Seebeck coefficients, and figure of merit of the β-bismuth monolayer and bulk Bi. Calculation reveals that low dimensionality can bring about the semimetal-semiconductor transition, decrease the lattice thermal conductivity, and increase the Seebeck coefficient of Bi. The relaxation time of electrons and holes is calculated according to the deformation potential theory, and is found to be more accurate than those reported in the literature. It is also shown that compared with Bi bulk, the β-bismuth monolayer possesses much lower electrical conductivity and electric thermal conductivity, while its figure of merit seems much bigger. The derived results are in good agreement with experimental results in the literature, and could provide a deep understanding of various properties of the β-bismuth monolayer.
第一性原理计算和玻尔兹曼输运理论相结合，用于对比研究β-铋单层和块状铋的能带结构、声子谱、晶格热导率、电子输运性质、塞贝克系数和优值。计算表明，低维结构可导致铋发生半金属-半导体转变，降低晶格热导率，并提高铋的塞贝克系数。根据形变势理论计算了电子和空穴的弛豫时间，发现其比文献报道的更为精确。研究还表明，与块状铋相比，β-铋单层的电导率和电热导率要低得多，但其优值似乎要大得多。所得结果与文献中的实验结果吻合良好，可为深入理解β-铋单层的各种性质提供依据。
