Bi4Se3薄膜的声子结构及电声子相互作用的第一性原理研究

基于密度泛函微扰理论，运用第一性原理研究两种终结面的Bi₄Se₃薄膜的声子结构和电-声子相互作用.结果表明两种终结面的Bi₄Se₃薄膜体系都是动力学稳定的. Bi₄Se₃薄膜中插入的Bi₂双原子层与Bi₂Se₃五原子层的声子投影态密度并不完全匹配，这会阻碍部分声子的输运，降低热导，从而有利于提高材料的热电性能.另外，两种终结面的Bi₄Se₃薄膜的电-声子耦合系数都不太大（约0.278），有利于制备基于室温工作的电子学器件.

Phonon Structure and Electron-phonon Interaction in Bi4 Se3 Film:First-principles Study

Based on density functional perturbation theory, phonon properties and electron-phonon interaction in Bi₄Se₃ film system are studied with first-principles calculations. It shows that dynamic of Bi₄Se₃ film system for two terminations is stable. There exists mismatch in projected phonon density of states between Bi₂ bilayer and Bi₂Se₃quintuple layer. It prevents part phonons to transport in Bi₄Se₃ film, which leads to thermal conductivity reduce and improves thermoelectric performance of material. Besides, electron-phonon coupling constant of Bi₄Se₃ film in two kinds of termination are small (about 0.278), which is in favour of electronic device in room temperature.