排序方式: 共有2条查询结果,搜索用时 0 毫秒
1
1.
本文利用分子动力学的方法和模拟退火技术从原子尺度分析研究了Si (100), Si (111)和Si (211)表面单原子层石墨烯的褶皱形貌及其演化特点. 研究表明, 分别置于Si晶体的三种不同原子表面的石墨烯都展现出原子尺度的褶皱形貌. 石墨烯与Si晶体表面原子的晶格失配是引起石墨烯褶皱的主要原因. 研究发现, Si晶体表面石墨烯的褶皱形貌强烈的依赖于退火温度. 石墨烯的褶皱形貌还将直接影响其在Si晶体表面的吸附稳定性. 这些研究结果有助于人们认识基于Si晶体衬底的石墨烯的结构形貌及其稳定性, 为石墨烯的进一步应用提供理论参考. 相似文献
2.
Excellent thermoelectric performance predicted in Sb2Te with natural superlattice structure 下载免费PDF全文
Using first-principles calculations combined with the Boltzmann transport theory, we explore the thermoelectric properties of natural superlattice (SL) structure Sb2Te. The results show that n-type Sb2Te possesses larger Seebeck coefficient of 249.59 (318.87) μV/K than p-type Sb2Te of 219.85 (210.38) μV/K and low lattice thermal conductivity of 1.25 (0.21) W/mK along the in-plane (out-of-plane) direction at 300 K. The excellent electron transport performance is mainly attributed to steeper density of state around the bottom of conduction band. The ultralow lattice thermal conductivity of Sb2Te is mainly caused by low phonon group velocity and strong anharmonicity. Further analysis shows that the decrease of group velocity comes from flatter dispersion curves which are contributed by the Brillouin-zone folding. The strong anharmonicity is mainly due to the presence of lone-pair electrons in Sb2Te. Combining such a high Seebeck coefficient with the low lattice thermal conductivity, maximum n-type thermoelectric figure of merit (ZT) of 1.46 and 1.38 could be achieved along the in-plane and out-of-plane directions at room temperature, which is higher than the reported values of Sb2Te3. The findings presented here provide insight into the transport property of Sb2Te and highlight potential applications of thermoelectric materials at room temperature. 相似文献
1