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摘要
Using a perturbative approach, the effects of the energy gap induced by the Aharonov-Bohm (AB) flux on the transport properties of defective metallic single-walled carbon nanotubes (MSWCNTs) are investigated. The electronic waves scattered back and forth by a pair of impurities give rise to Fabry-Perot oscillations which constitutes a coherent backscattering interference pattern (CBSIP). It is shown that the CBSIP can be aperiodically modulated by applying a magnetic field parallel to the nanotube axis. In fact, the AB-flux brings this CBSIP under control by an additional phase shift. As a consequence, the extrema as well as zeros of the CBSIP are located at the irrational fractions of the quantity Phi(rho) =Phi /Phi(0), where Phi is the flux piercing the nanotube cross section and Phi(0) = h/e is the magnetic quantum flux. Indeed, the spacing between two adjacent extrema in the magneto-differential conductance (MDC) profile is decreased with increasing magnetic field. The faster and higher and slower and shorter variations are then obtained by metallic zigzag and armchair nanotubes, respectively. Such results lead to the proposal that defective metallic nanotubes could be used as magneto-conductance switching devices based on the AB effect.
- 出版日期2008-2-20
