Si(111)面电子结构、表面能和功函数的第一性原理研究(英文)

First-Principles Study of Electronic Structure,Surface Energy,Work Function of Si(111) Surface

本文采用基于密度泛函理论(DFT)框架下的平面波超软赝势法研究了体相Si和Si(111)面。计算得到的体相Si的晶格常数、体积模量和结合能较好地与其它文献结果吻合。在表面结构中,由于Si-3p态的影响导致键长和电荷密度的改变。键长在第一二层,二三层和三四层之间由2.338(?)变为2.286(?),2.382(?),2.352(?),电荷密度由0.57946×10~3 electrons/nm^3变为0.60419×10~3,0.5143×10~3和0.55925×10~3electrons/nm^3。计算得到的Si(111)的表面能和功函数为Si的应用提供了理论依据。

The bulk Si and slab Si （111） were studied using the plane-wave uhrasofi pseudopotential technique based on the first principles density functional theory （DFT）. The lattice parameter, equilibrium volume, bulk modulus and cohesive energy of Si were calculated and found to agree with the previous works. Because of the surface states caused by Si-3p state, the length of bonds and the charge density are all changed. The length of bonds between the first and the second layer, the second and the third layer, the third and the fourth layer is changed from 2. 338A to 2. 286A, 2. 382A, 2. 352 A respectively, and the consequence of this displacement is the change in charge density from 0. 57946×103 electrons/nm^3 to 0. 60419×10^3 , 0. 5143×10^3 and 0. 55925×10^3 electrons/nm^3 respectively. The surface energy and work function of the Si （111 ） slabs have been calculated, offering a theoretical basis for the application of Si.