Ulpe Anna C, Bauerfeind Katharina C L, Bredow Thomas
Mulliken Center for Theoretical Chemistry, Institut für Physikalische und Theoretische Chemie, Universität Bonn, Beringstr. 4-6, 53115 Bonn, Germany.
ACS Omega. 2019 Feb 25;4(2):4138-4146. doi: 10.1021/acsomega.8b03254. eCollection 2019 Feb 28.
This work is a systematic ab initio study of the influence of spin state and cation distribution on the stability, dielectric constant, electronic band gap, and density of states of ternary transition-metal oxides. As an example, the chemical family of spinel ferrites MFeO, with M = Mg, Sc-Zn is chosen. Dielectric constant and band gap are calculated for various spin states and cation configurations via dielectric-dependent self-consistent hybrid functionals and compared to available experimental data. When choosing the most stable spin state and cation configuration, the calculated electronic properties are in reasonable agreement with measured values. The nature of the excitation is investigated through projected density of states. A pronounced dependence of band gap energy and dielectric constant on the spin state and cation configuration is observed, which is a possible explanation for the large variation of the experimental results, in particular, if several states are energetically close.
这项工作是对自旋态和阳离子分布对三元过渡金属氧化物的稳定性、介电常数、电子带隙和态密度的影响进行的系统从头算研究。作为一个例子，选择了尖晶石铁氧体MFeO的化学族，其中M = Mg，Sc - Zn。通过依赖于介电常数的自洽混合泛函计算了各种自旋态和阳离子构型的介电常数和带隙，并与现有的实验数据进行了比较。当选择最稳定的自旋态和阳离子构型时，计算得到的电子性质与测量值合理吻合。通过投影态密度研究了激发的性质。观察到带隙能量和介电常数对自旋态和阳离子构型有明显的依赖性，这可能是实验结果存在较大差异的一个解释，特别是如果几种状态在能量上相近的话。
