BN纳米带几何结构和电子性质第一性原理研究

摘要

The geometrical structures and electronical properties of BN nanobelts with different width are investigated by first-principles study. The results show that with the increase of the belt's width, the structure of BN nanobelt's edge structure changes significantly. The bond angle and B-B bond length increase, B-B bond rupture when belt's width achieve 1.7 nm. The results of electronical properties show that with the decrease of the belt's width, the energy gap between the lowest unoccupied molecular orbital ( LUMO) and the highest occupied molecular orbital (HOMO) decrease drastically, the density of states (DOS) at Fermi level increase and pseudogap decrease .%采用第一性原理研究了不同带宽下BN纳米带的几何结构与电子性质.研究结果表明:随着带宽的增大,BN纳米带边缘发生形变,键角增大,B-B键键长增大.当带宽约为1.7 nm时,B-B键发生断裂.电子性质研究表明:随带宽减小,最高占据轨道(HOMO)/最低非占据轨道(LUMO)能隙减小.对电子态密度(DOS)及赝能隙分析表明:BN纳米带带宽越小,在费米能级处DOS越大,且赝能隙越小.这和GNR比较相似,说明BN纳米带越窄电子越容易从价带向导带跃迁.