具有空位缺陷的碳纳米管的铁磁性  

Ferromagnetism of Carbon Nanotube with Vacancy Defects

作　　者：杨善明[1] 朱丽娅[1] 王为忠[1] 

机构地区：[1]武汉大学物理科学与技术学院,湖北武汉430072

出　　处：《武汉大学学报（理学版）》2009年第2期167-170,共4页Journal of Wuhan University:Natural Science Edition

基　　金：国家自然科学基金资助项目(50573059)

摘　　要：利用Hubbard模型,采用数值计算的方法研究了空位缺陷附近的碳原子间的跳跃积分(t2)和在位库仑相互作用(U)对碳纳米管的铁磁基态的影响.当t2<0.5时,系统基态具有亚铁磁性,并且单位缺陷的自旋S=1/2,体系磁性主要来源于缺陷附近和纳米管两端格点自旋.随着t2增大到临界值t2c后,体系的亚铁磁基态变得不稳定,并且t2c的大小依赖于在位的库仑相互作用U.自旋密度计算表明:t2能抑制自旋关联并使体系的亚铁磁性基态不稳定.The ferromagnetism of carbon nanotube with vacancy defects is investigated with the Hubbard model. For small hopping integral （t2） around the defects, the ferrimagnetic ground state with spin S= 1/2 per defect is obtained and the ferrimagnetism is mainly contributed by the spin at the carbon atoms around the defects and the two ends of the tube. As t2 increases to a critical value t2c, which depends on the on-site Coulomb repulsion U, the ferrimagnetic ground state is unstable. The calculation of spin density shows that t2 suppresses the spin correlation and destabilizes the ferrimagnetic ground state.

关 键 词：空位缺陷 铁磁性 基态 能隙 自旋密度 碳纳米管 

分 类 号：O482.5[理学—固体物理]