双空位缺陷对金属性碳纳米管量子电子学特性的影响研究

Influence of Divacancies on the Quantum Electronic Properties of Metallic Carbon Nanotubes

采用第一性原理的密度泛函理论计算方法,研究了2种不同分布的双原子空位缺陷(平行于管轴和斜交于管轴)对金属型(12,0)碳纳米管量子电子特性的影响。研究结果表明,平行于管轴的五边形-八边形-五边形(5-8-5)缺陷的转变能是最小的,是最稳定的缺陷结构分布;平行于管轴的5-8-5缺陷和斜交于管轴5-8-5缺陷都在价带部分引入了出现2个电子背散射中心,这对电子输运非常不利;斜交于管轴5-8-5缺陷比平行于管轴5-8-5缺陷对电导的抑制作用更大,这是由于斜交于管轴5-8-5缺陷破环了碳纳米管的轴向对称性。

By using the first principle density functional theory,the effect of different distribution divacancies on the quantum electronic properties of metallic carbon nanotube is investigated.The results reveal that the parallel pentagon-octagon-pentagon(5-8-5) defects are the most stable defects in the carbon nanotubes because of their lowest transformation energy.Both parallel 5-8-5 defects and titled 5-8-5 defects rise to two backscattering centers that are located below the Fermi level,which is unfavorable for electronic transport.In addition,the effect of titled 5-8-5 defects on the suppression of conductance is more prominent than that of the parallel 5-8-5 defects.This phenomenon is attributed to the breaking of axial symmetry of the carbon nanotube by the presence of titled 5-8-5 defects.