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Exotic optical and transport properties of carbon nanotubes

碳纳米管的奇异光学和传输特性

基本信息

批准号：
16540281
负责人：
ANDO Tsuneya
金额：
$ 2.43万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

项目摘要

A carbon nanotube is composed of concentric tubes of rolled two-dimensional graphite sheets, on which hexagons are arranged in a helical fashion about the axis. The diameter of a multi-wall nanotube ranges from 2 to 30 nm and that of a single-wall nanotube lies between 0.7 and 1.6 nm. The maximum length of nanotubes exceeds 1 um. Since the first discovery quite a number of studies have been reported on their electronic properties because of their unique topological structures. The purpose of this project is to study quantum transport in carbon nanotubes and their composite systems with special emphasis on topology of nanotubes.The subjects include the presence of special time reversal symmetry leading to the symplectic universality responsible to the absence of backscattering and the presence of a perfectly conducting channel, effects of various perturbations destroying the symmetry, and the singular dynamical conductivity associated with the perfect channel. Effects of electron-electron interaction on the band structure, strong exciton effects in optical properties, the fine structure of excitons (dark and bright) due to short-range Coulomb interaction and exchange effect and its change in Aharonov-Bohm magnetic flux, and exciton peaks for light polarized perpendicular to the axis were also studied. Further, the absence of inter-wall interaction in usual incommensurate multi-wall nanotubes and effects of electron-phonon interactions on optical phonons and their behavior in the Aharonov-Bohm flux were clarified.

碳纳米管是由二维石墨片制成的同心管组成，其上的六边形围绕轴以螺旋方式排列。多壁纳米管的直径范围为2至30 nm，单壁纳米管的直径范围为0.7至1.6 nm。纳米管的最大长度超过1 μ m。由于其独特的拓扑结构，自首次发现以来，人们对其电子性质进行了大量的研究。本项目的目的是研究碳纳米管及其复合体系中的量子输运，重点是碳纳米管的拓扑结构，研究的课题包括特殊的时间反演对称性的存在导致了辛普适性，这是导致不存在背散射和存在完美导电通道的原因，各种扰动破坏对称性的影响，以及与理想沟道相关的奇异动态电导率。研究了电子-电子相互作用对能带结构的影响，强激子效应对光学性质的影响，短程库仑相互作用和交换效应引起的激子（暗激子和亮激子）的精细结构及其对Aharonov-Bohm磁通量的影响，以及垂直于轴偏振光的激子峰.进一步阐明了通常的无公度多壁纳米管中不存在壁间相互作用，以及电子-声子相互作用对光学声子及其在Aharonov-Bohm通量中行为的影响。