B（N）掺杂单壁碳纳米管的Al原子吸附性能的第一性原理研究

采用基于密度泛函理论的平面波赝势方法和广义梯度近似，对未掺杂、掺B、掺N的碳纳米管(CNT)不同位置上Al原子的吸附进行了几何优化，计算了吸附Al、掺杂前后CNT的能带结构、态密度、差分电荷密度、电荷布居数和吸附能.计算结果表明，掺B使CNT形成缺电子状态，利于具有自由电子的Al原子的吸附结合，可显著提高Al在金属性的(5，5)CNT和半导性的(8，0)CNT外壁的吸附能；掺杂N形成多电子状态，在费米能级附近半满的施主能级也利于填充Al的价电子，改善Al在(5，5)CNT和(8，0)CNT外壁的吸附结合性 关键词： 密度泛函理论 单壁碳纳米管 B(N)掺杂 Al原子吸附

First-principle study of the effect of boron (nitrogen)-doping on adsorbing characteristics of aluminum on single-walled carbon nanotubes

The geometrical structures of adsorbed aluminum atoms on different sites of undoped and boron (nitrogen)-doped single-walled carbon nanotubes (SWCNTs) were optimized using plane wave pseudopotential method with generalized gradient approximation based upon the density functional theory. The band structures，density of states，electron density difference，Mulliken population， adsorption energies of both undoped and boron (nitrogen)-doped SWCNTs were calculated theoretically. The results revealed that boron-doping enhances the adsorption energy E_a of Al on metallic (5，5) CNTs and semiconducting (8，0) CNTs by forming an electron-deficient structure filled with the electrons offered by Al atom. Meanwhile the results also suggest that nitrogen-doping increases E_a of Al on SWCNTs by forming electron-rich half-filled donor structure around Fermi level filled with the electrons of Al atom. Boron- and nitrogen-doping enhance the adsorption energy E_a by forming ionic-bond-type and covalent-bond-type bonds， respectively. The doping effect may also be beneficial to strengthening contact of interfaces between Al matrix and CNTs.