拉伸形变下BC_3纳米管的能带结构  

Band structures of strain-deformed BC_3 nanotubes

作　　者：韩文鹏[1] 刘红[1] 

机构地区：[1]南京师范大学物理系,南京210046

出　　处：《物理学报》2010年第6期4194-4201,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:10947004);江苏省自然科学基金(批准号:BK2008427);高等学校博士学科点专项科研基金(批准号:200803190004)资助的课题~~

摘　　要：运用紧束缚能带理论,研究拉伸形变下BC3纳米管的能带结构.研究表明:随着拉伸和压缩强度的不断增加,BC3纳米管的导带能级和价带能级逐渐靠近,最终发生能带交叠.压缩形变下能带的交叠程度可达0.5eV,而拉伸形变下只有0.2eV.对于扶手椅型BC3纳米管,随着拉伸和压缩的不断增加,BC3纳米管首先由直接半导体转化为间接半导体,进而发生能带的交叠,表现出金属性.在无形变时,扶手椅型BC3纳米管是一种很不稳定的直接跃迁窄带半导体,轻微的压缩形变(et=-0.003)都可以使其转化为间接半导体.对于锯齿型BC3纳米管,由于存在平坦的导带和价带,轻微的拉伸和压缩形变会使原来全波矢允许的直接跃迁变为只允许一个波矢的直接跃迁.By using the tight-binding energy band theory,we study the band structures of BC3 nanotubes under stretching and compressing deformations,the conductivity band turns more and more close to the valence band of the BC3 nanotubes and eventually they overlap each other with the increase of tension. Furthermore,the results obtained show that the overlap under compressing is bigger than that under stretching. The biggest overlap under compressing is up to 0. 5 eV,but it is only 0. 2 eV under stretching. In addition,for armchair BC3 nanotubes,the results of band structures show that with the increase of tension,the BC3 nanotube transforms into an indirect semiconductor from a direct semiconductor,and then leads to the band overlap. The armchair BC3 nanotube is an unstable narrow-gap semiconductor,because a little compress （et =-0. 003） can convert it transform into an indirect semiconductor from a direct semiconductor. For zigzag BC3 nanotubes,a slight deformation can turn into a direct semiconductor having only one allowed wave vector from a direct semiconductor having all wave vectors,owing to the existence of two flat conductivity and valence bands.

关 键 词：BC3纳米管 能隙 拉伸形变 半导体 

分 类 号：TB383.1[一般工业技术—材料科学与工程]