【摘要】 采用基于第一性原理的密度泛函理论(DFT)和局域密度近似(LDA)方法,优化计算得到碳纳米管(CNT),硼原子取代碳原子及其吸附氖原子前后系统的几何结构,能量,电子能带和态密度.结果显示,碳纳米管的能带结构与石墨的层状几何结构相似,能量的变化只在kz=0和kz=0.5平面之间沿着c轴方向出现.B原子取代C原子使价带和导带分别分裂为两个和三个能带.对Ne原子的吸附使价带能量沿着c轴方向升高并导致Fermi面附近的态密度下降.Ne原子的吸附在谷位H最稳定,顶位A其次.C-C间σ键的弯曲使Ne原子吸附在桥位b1比桥位b2处更为稳定.Ne原子在管外的吸附均为放热过程,而管内则为吸热过程.结构分析表明Ne原子对C原子有排斥作用,对B原子却具有吸引作用.B原子取代C原子的位置略凸出于CNT的管壁之外,使Ne原子的吸附能增加.更多还原

【Abstract】 Based on density functional theory( DFT) and local density approximation( LDA) methods,the geometries,the energies,electronic bands and density of states are optimized and calculated for the adsorption of neon atoms on carbon nanotubes( CNT) doped with boron atoms. The results show that the energy bands of CNT have a topology similar to the layered geometry of graphite. The energy changes of the bands between the two planes of kz= 0 and kz= 0. 5 occur only along the c- axis direction. The substituting boron atom splits the valence and conduction bands into two and three energy bands,respectively. The adsorption of neon atom makes the energy of the valence band rise along the c- axis direction,and the density of states near the Fermi surface decreases. The valley site H is the most stable site for the adsorption of neon atom,and the top site A is the second. The bending of the carbonic σ bond along the circumferential direction makes the bridge site b1 more stable for the adsorption of neon than the bridge site b2. All the adsorptions of neon atoms outside of the CNT are exothermic; however that inside the tube endothermic. The analysis shows the repulsion of the neon on carbon atomsand the attraction to the boron atom. Protruding slightly beyond the wall of the CNT,the substituting boron atom makes the adsorption exothermic energy of neon atom increase.更多还原