First-principles study of magnetism driven by intrinsic defects in MgO
First-principles study of magnetism driven by intrinsic defects in MgO
复制标题
MgO本征缺陷驱动磁性的第一性原理研究
DOI：
10.1016/j.ssc.2009.03.010
复制
发表时间：
2009-06-01
影响因子：
2.1
通讯作者：
Jiang, Minhua
中科院分区：
文献类型：
--
作者：
Gao, Feng;Hu, Jifan;Jiang, Minhua
用第一性原理方法研究了含中性点缺陷MgO的d（0）铁磁性。采用广义梯度近似（GGA）、局域密度近似（LDA）和具有在位效应的局域密度近似（LDA + U）方法计算交换关联能。未掺杂的MgO被发现是不稳定的。超晶胞中的中性氧空位不产生铁磁性，而中性镁空位则产生大的磁矩。氧原子的2 p电子的自旋极化是产生感生磁矩的原因。随着V-Mg（0）空位浓度的增加，铁磁矩增强。铁磁性敏感地依赖于Mg空位的分布。V-Mg（0）空位在MgO晶格中可能存在优先占位。LDA + U计算表明，浓度为6.25%的V-Mg（0）空位可以将MgO绝缘体转化为半金属。我们的结果可能是有效的纳米表面附近的区域。(C)2009爱思唯尔有限公司保留所有权利。
The d(0) ferromagnetism of MgO containing neutral point defects has been investigated using the first-principles method. The generalized gradient approximation (GGA), local density approximation (LDA) and local density approximation with on-site effect U (LDA + U) schemes were employed to describe the exchange correlation energy. Undoped MgO is found to be nonmagnetic. Neutral oxygen vacancies in the supercell induce no ferromagnetism, while neutral Mg vacancies could bring about large magnetic moments. The spin polarization of 2p electrons of oxygen atoms is responsible for the induced magnetic moments. The ferromagnetic moments enhance with an increase of the concentration of V-Mg(0) vacancies. Ferromagnetism depends sensitively on the distribution of Mg vacancies. There may be a preferable occupation for V-Mg(0) vacancies in the MgO lattice. The LDA + U calculation indicates that a concentration of 6.25% V-Mg(0) vacancies could convert the MgO insulator to half-metal. Our results may be valid for the region near the surface of nanograms. (C) 2009 Elsevier Ltd. All rights reserved.