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利用第一性原理及Stillinger-Weber(SW),EDIP和Tersoff经验势函数对比研究了硅中单空位(V1)、双空位(V2)和六边形空位环(V6)的结构特性及形成能.讨论了经验势函数描述空位时的优点和缺点.结果发现,第一性原理方法可以精确描述空位的原子结构及能量特性,而短程有效的经验势函数无法描述空位所固有的量子效应,如Jahn-Teller变形等.另外,由于经验势函数自身的缺陷,EDIP和T3无法应用于空位结构特性的计算.虽然SW势函数也无法描述V1及V2的点群,但是考虑到它在空位弛豫方向及形成能计算中表现出的优异性能,相对于EDIP及T3更适合于空位的计算.
The structural properties and formation energies of single vacancy (V1), double vacancy (V2) and hexagonal vacancy ring (V6) in silicon were compared using first-principles and the empirical potentials of Stillinger-Weber (SW), EDIP and Tersoff The advantages and disadvantages of empirically potential functions in describing vacancies are discussed.It is found that the first principles method can accurately describe the atomic structure and energy properties of vacancies and that the short-range empirical potential functions can not describe the inherent quantum effects of vacancies. Jahn-Teller deformation, etc. In addition, EDIP and T3 can not be applied to the calculation of the structural properties of vacancies due to the inherent potential shortcomings of the empirical potential function.Although the SW potential function can not describe the point group of V1 and V2, Direction and formation can be calculated in the performance of the excellent performance, relative to EDIP and T3 is more suitable for the calculation of vacancy.