Jhi Seung-Hoon, Louie Steven G, Cohen Marvin L
Department of Physics, University of California at Berkeley and Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Phys Rev Lett. 2005 Nov 25;95(22):226403. doi: 10.1103/PhysRevLett.95.226403. Epub 2005 Nov 23.
The electronic structures of carbon nanotubes doped with oxygen dimers are studied using the ab initio pseudopotential density functional method. The fundamental energy gap of zigzag semiconducting nanotubes exhibits a strong dependence on both the concentration and configuration of oxygen-dimer defects that substitute for carbon atoms in the tubes and on the tube chiral index. For a certain type of zigzag nanotube when doped with oxygen dimers, the energy gap is closed and the tube becomes semimetallic. At higher oxygen-dimer concentrations the gap reopens, and the tube exhibits semiconducting behavior again. The change of the band gap of the zigzag tube is understood in terms of their response to the strains caused by the dimer substitutional doping.
采用从头算赝势密度泛函方法研究了掺杂氧二聚体的碳纳米管的电子结构。锯齿形半导体纳米管的基本能隙强烈依赖于替代管中碳原子的氧二聚体缺陷的浓度和构型，以及管的手性指数。对于某一类型的锯齿形纳米管，当掺杂氧二聚体时，能隙关闭，纳米管变为半金属性。在较高的氧二聚体浓度下，能隙重新打开，纳米管再次表现出半导体行为。锯齿形管带隙的变化可以根据它们对二聚体替代掺杂引起的应变的响应来理解。
