YFeO3的电子结构和光学性质的第一性原理研究

稀土正铁氧体YFeO₃呈正交钙钛矿结构,其晶体和纳米晶材料在电极材料、 传感器和光催化领域具有重要的应用价值.用平面波赝势方法,采用广义梯度近似、改进的Perdew-Burke-Emzerhof交换-关联势、 实空间超软赝势计算方案,研究了YFeO₃晶体的几何结构、电子结构和光学性质. 计算得到的晶格参量与报道的实验结果一致.通过对能带结构、态密度、介电函数、吸收系数和光电导率的计算和分析, 确定YFeO₃是直接能隙半导体,能隙E_g约为2.22 eV,阐明了YFeO₃晶体和纳米晶具有较好的可见光催化性能.

First-principles study on the electronic structure and optical properties of YFeO3

Rare-earth orthoferrites (such as YFeO₃) with orthorhombic perovskite-type structure are promising candidates in the fields of electrode materials, gas sensors and photocatalysts. The geometric structure, the electronic structure and the optical properties of YFeO₃ crystal are investigated by using the plane-wave pseudo-potential method, with the scheme of generalized gradient approximation, revised Perdew-Burke-Emzerhof exchange-correlation potential and ultrasoft pseudopotential. The obtained lattice parameters are in good accordance with experimental results reported. The results confirm that YFeO₃ crystal is a direct semiconductor with a gap (E_g) of about 2.22 eV, based on the analyses about band structure, density of state, dielectric function, absorption coefficient, and photoconductivity. It is clarified that YFeO₃ crystal and nanocrystalline possess good photocatalytic activities for visible light.