使用密度泛函理论对Fe3O4(111),(110)和(001)的表面结构及稳定性进行了研究。Fe3O4(111)表面有六种不同的终结形式,其中以四面体或八面体铁层终结的结构最稳定。对于(110)和(001)表面而言,分别有两种终结,且能量相近。计算结果与实验结果非常吻合并且合理解释了实验结果的争议性和复杂性。表面自由能的计算表明,(111)表面在热力学上不如(110)和(001)表面稳定,它的形成应该是动力学控制过程。
The surface structures of Fe3O4(111),(110) and(001) have been studied at the level of density functional theory.It is found that there are two most stable Fe3O4(111) surfaces in close energy and terminated with the exposed tetrahedral and octahedral iron layers.Both Fe3O4(110) and Fe3O4(001) surfaces have two surface terminations in close energy.The computed results agree well with the experiments,and explain reasonably the observed diversity and complexity of the experiments.The computed surface free energies indicate that(111) is less favourable thermodynamically than(110) and(001),and the formation of(111) should be kinetic controlled.