Ning Lixin, Zhang Yongfan, Cui Zhifeng
Department of Physics, Anhui Normal University, Wuhu, Anhui 241000, People's Republic of China.
J Phys Condens Matter. 2009 Nov 11;21(45):455601. doi: 10.1088/0953-8984/21/45/455601. Epub 2009 Oct 23.
The structural and electronic properties of lutecia (C-type Lu(2)O(3)) have been investigated using the projected augmented wave (PAW) method based on the periodic density functional theory (DFT). Two models for the localized Lu 4f electrons have been employed, in which the f electrons are treated as a part of the inner core and as valence electrons, respectively. With the former model, the Perdew-Burke-Ernzerhof (PBE) calculations yield a crystal structure in good agreement with experiments, while with the latter model, the PBE+U results show that the optimum U(eff) parameter value is dependent on the property investigated. The variation of structural properties with respect to the model used and the U(eff) value chosen has been rationalized in terms of the repulsive interaction between Lu 4f and O 2p electrons owing to the insufficient self-interaction cancelation associated with the localized f electrons in the DFT functional. Based on the calculated results, a practical scheme is proposed for the calculation of Lu(2)O(3) and the related materials in cases where the f electronic properties are relevant.
基于周期性密度泛函理论（DFT），采用投影增强波（PAW）方法研究了镥氧化物（C型Lu₂O₃）的结构和电子性质。采用了两种处理局域化Lu 4f电子的模型，其中f电子分别被视为内芯的一部分和价电子。在前一种模型中，Perdew-Burke-Ernzerhof（PBE）计算得到的晶体结构与实验结果吻合良好，而在后一种模型中，PBE+U结果表明最佳U(eff)参数值取决于所研究的性质。由于DFT泛函中与局域化f电子相关的自相互作用抵消不足，导致Lu 4f和O 2p电子之间存在排斥相互作用，据此解释了结构性质随所用模型和所选U(eff)值的变化。基于计算结果，针对f电子性质相关的情况，提出了一种计算Lu₂O₃及相关材料的实用方案。
