新半金属Fe_2LaO_4磁电性能的第一性原理计算  

First-principle Calculation on the Magnetic and Electric Properties of New Half-metal Fe_2LaO_4

作　　者：刘俊[1] 陈希明[1] 董会宁[1] 

机构地区：[1]重庆邮电大学应用物理研究所

出　　处：《无机化学学报》2007年第11期1857-1863,共7页Chinese Journal of Inorganic Chemistry

基　　金：重庆市自然科学基金(No.CSTC2005BB4070);重庆市教委项目(No.kj060515;kj050502)资助项目

摘　　要：利用基于密度泛函理论的第一性原理赝势法设计并优化了含稀土元素的新半金属Fe2LaO4。详细计算了其电荷分布,分子磁矩等磁电性能,并结合配位场理论分析了其电子结构。结果表明,Fe2LaO4是一种含稀土元素的铁磁性的新ⅡB型半金属;它的稳定相晶格常数约为0.623nm,分子磁矩约为1.0μB;Fe2LaO4属软铁磁性半金属;La较多的外层电子增强了Fe2LaO4内部的库仑斥力,导致了配合物ML4和ML6均受强场作用,从而使Fe2LaO4具有软铁磁性;考虑自旋分布后ML4和ML6的电子结构分别为a1g1↑a1g1↓t1u3↑t1u3↓eg2↑eg2↓t2g3↑t2g3↓和a1g1↑a1g1↓t1u3↑t1u3↓t2g3↑t2g3↓eg2↑eg2↓eg*1↑,这些电子属于分子轨道。New rare-earth half-metal Fe2LaO4 is designed, and then is geometrically optimized with the first-principle pseudo-potentials based on the density functional theories. The magnetic and electric properties including the charge order and the molecular magnetic moments of Fe2LaO4 are calculated in system. Then the electronic structures of Fe2LaO4 are analyzed from coordinate field theories. From our calculation, Fe2LaO4 is a new rare-earth ferromagnetic Ⅱ B-type half-metal. For Fe2LaO4, the stable lattice constant is about 0.623 nm and the molecular magnetic moment is about 1.0μB. The mechanism of soft magnetism of Fe2LaO4 is that La has more outermost electrons than Fe so that the crystal field of the coordinate compounds ML, and ML6 of Fe2LaO4 is very strong. The average electronic structures of ML, and ML6 can be approximatively written as a1g^1↑a1g^1↓t1u^3↑t1u^3↓eg^2↑eg^2↓t2g^3↑t2g^3↓ and a1g^1↑a1g^1↓t1u^3↑t1u^3↓t2g^3↑t2g^3↓eg^2↑eg^2↓eg^＊1↑, respectively.

关 键 词：Fe2LaO4 新半金属 磁电性能 电子结构 分子磁矩 

分 类 号：O614.811[理学—无机化学] O614.331[理学—化学]