用金属势函数描述氧化物是实现金属-氧化物界面分子动力学模拟的关键.基于此,通过拟合α-Al2O3的晶格能、晶格常数、弹性常数,获得了一套用于描述α-Al2O3的长程Finnis-Sinclair(F-S)势.通过与已报道的描述α-Al2O3的EAM势、Glue势和modifiedMatsui(m-Matsui)势的比较,结果达到或优于前人的结果.进而,在300K的温度下对α-Al2O3体系进行了MD模拟,模拟结果与实验值也符合较好,证明了本套势参数对α-Al2O3及Fe-Al2O3界面描述的适用.
The molecular dynamics (MD) simulation of metal-metal oxide interface requires a uniform potential to simultaneously describe metal and metal oxide. Accordingly, we obtained a set of long-range Finnis-Sinclair (F-S) potential parameters of α-Al_2O_3. All of the parameters were fitted to the targets, i.e. the experimental lattice energy, lattice constants, and elastic constants of α-Al_2O_3. Meanwhile, we compared our results with those reported by EAM, Glue and modified Matsui (m-Matsui) potentials and found that our rcsults are equivalent or better. After that, MD simulation of α-Al_2O_3 at 300 K with our long-range F-S potential was performed and the pair correlation functions, coordination numbers were calculated. The good agreement between calculation results and experiments validated the feasibility of this set of F-S potential parameters to the description of α-Al2O3 system.