Research On Electronic Transport Of Carbon Nanotube Quantum Dot

Carbon nanotube quantum dots are promising candidates of quantum electronic device for future applications, and have been researched on their every aspect. The quantization of the electronic charge resulting from their meso-scopic sizes and the layouts generates several typical transport phenomenons. The blockade and the resonance are two basic and important ones. While the Coulomb Blockade effect simply results from the Coulomb repulsion, and the Franck-Condon Blockade concerns the excitation of the CNT lattice, the Kondo effect is a typical many-body shielded effect.In this letter we combine the slave-bosen technique and the equation of motion for Green functions to study the phonon-assisted transport of the carbon nanotube quantum dot at zero temperature which involves strong electronic spin-orbit coupling. The coupling splits the fourfold degenerate energy level into two levels corresponding to the parallel and antiparallel configurations of spin and orbit. The split generates an additional Kondo peak in the local density of states(LDOS). When the electron-phonon interactions are involved, more phonon-associated Kondo peaks appear in the LDOS, and the peaks are sharper and narrower for the stronger E-P interactions and larger phonons.