摘要
利用密度泛函理论中的广义梯度近似对CoBn（n=1～7）团簇的结构、稳定性和磁性进行了分析。综合CoBn团簇基态的平均结合能、二阶能量差分、垂直电离势、最高占据分子轨道与最低未占据分子轨道之间的能隙分析可知，n=3和7的三维团簇的稳定性表现突出。Mullikcn布局分析表明体系的磁矩主要来自局域d电子的贡献。CoBn团簇中Co原子的磁矩和总磁矩分别在1≤n〈3和4≤n〈7振荡变化，在n=3和7发生“猝灭”。CoB3和CoB7团簇较高的稳定性和“磁矩猝灭”是由于较多的电荷转移和在费米能级强烈的spd杂化。
The structural and magnetic properties of CoBn clusters （n=1-7） have been investigated by using the generalized gradient approximation （GGA） in density functional theory. The calculated results on the averaged binding energy, second-order difference of cluster energies, the vertical ionization potentials and HOMO-LUMO gaps indicated that the stability of three dimensional structures is more prominent for n=3 and 7. Mulliken population analysis result indicated that the magnetic moment of CoBn clusters mainly comes from the localized d electron. The magnetic moments of CoB, clusters show even-odd alternating pattern for 1≤n〈3 and 4≤n〈7. However, the magnetic moment of CoBn clusters is quenched at n=3 and 7. The charge transfer and strong hybridization between s, p and d states might be one major reason for the stronger stability and quenching of the magnetic moment of CoB3 and CoB7 clusters.
出处
《磁性材料及器件》
CSCD
北大核心
2009年第3期12-14,共3页
Journal of Magnetic Materials and Devices
基金
河南省教育厅科技攻关资助项目(2007480001)
关键词
CoBn团簇
密度泛函理论
结构与稳定性
磁性
CoB. clusters
density functional theory
structure and stability
magnetism
