(Cu,Mn)_(3)O_(4)尖晶石晶体的第一性原理研究

First Principles Study of(Cu,Mn)_(3)O_(4)Spinels

利用基于密度泛函理论方法,构建了不同Mn、Cu比例的Mn_(2)CuO_(4)和MnCu_(2)O_(4)尖晶石晶体模型,优化了晶体模型的结构,分析并揭示了两种尖晶石晶体的导电性质和光学性质随Mn、Cu比例的变化规律。计算结果表明,当Mn-Cu比例由2:1变为1:2时,尖晶石体系的带隙宽度会变窄。通过分波态密度分析可知,这是由于Cu比例增高导致体系费米能级附近的d态电子增加引起的,故而MnCu_(2)O_(4)表现出更好的导电性。而Mn_(2)CuO_(4)尖晶石具有更小的静态介电函数值,即Mn_(2)CuO_(4)载流子迁移率较小。分析光吸收和光反射函数图可知,Mn_(2)CuO_(4)与MnCu_(2)O_(4)均对紫外线区域具有强烈的吸收和反射作用。该工作可以推动(Cu,Mn)3 O_(4)系尖晶石晶体在金属连接体涂层上的应用。

Based on density functional theory,the(Cu,Mn)_(3)O_(4)spinels of Mn_(2)CuO_(4)and MnCu_(2)O_(4)crystal models are built,and the simulation is done.Then,the structures of the models are optimized,and the conductivity and optical properties of the two spinel crystals are analyzed and revealed.The simulation results show that the band gap of the spinel crystal becomes smaller when the ratio of Mn-Cu changes from 2∶1 to 1∶2.This is due to the fact that the increasing Cu ratio leads to the increasing d-state electrons at the Fermi level of the system through the partial density of states analysis.Therefore,MnCu_(2)O_(4)spinel displays better conductivity.And the static dielectric constant of Mn_(2)CuO_(4)spinel is smaller,which indicates its smaller intrinsic carrier concentration.The calculations of the optical absorption and reflection properties show that both of the studied spinels have strong absorption and reflection effects on the ultraviolet region.This can provide guidance for promoting the industrial application of(Cu,Mn)_(3)O_(4)spinels on metallic interconnects.