铁酸锌(311)表面结构的密度泛函理论研究

利用原子层沉积技术（ALD）合成了铁酸锌（ZnFe₂O₄）纳米颗粒。基于密度泛函理论和原子热力学的方法，计算了ZnFe₂O₄的结构、磁性和电子性质，研究了ZnFe₂O₄（311）面六种不同终结面的稳定性与氧化学势和锌化学势的关系。结果表明，ZnFe₂O₄是具有正尖晶石结构的半导体，禁带宽度为1.91 eV，且具有反铁磁性。在ZnFe₂O₄可以稳定存在的化学势范围内，O₁、O₂、Fe₂、Zn₂四种终结面可以稳定存在，且具有不同的稳定区间。在富锌条件下（△μ_Zn=0 eV），O₁终结面在大部分O化学势范围内最稳定，在贫锌条件下（△μ_Zn=-3.88 eV），O₂终结面变得最稳定。

Surface structure of zinc ferrite (311)-A density functional theory study

Zinc ferrite (ZnFe₂O₄) nanoparticles were synthesized by atomic layer deposition (ALD). The structure, magnetic and electronic properties of ZnFe₂O₄ were investigated by density functional theory (DFT) and atomic thermodynamics methods; the stabilities of ZnFe₂O₄ (311) surface with six different terminations were considered and the surface energies were related to O and Zn chemical potential corresponding to environment. The results indicate that bulk ZnFe₂O₄ has a normal spinel structure; it is an antiferromagnetic semiconductor with a band gap of 1.91 eV. Only four out of six possible terminations, that is, O₁, O₂, Fe₂ and Zn₂ terminations, can be stable within allowed region. In particular, the O₁ termination is stable over a wide range of △μ_O under Zn-rich conditions (△μ_Zn=0 eV), whereas the O₂ termination turns to be most stable in Zn-poor environment (△μ_Zn=-3.88 eV).