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We study the Kondo effect in a CNT(left lead)-CNT(QD)-CNT(right lead) structure. Here CNT is a single-wall metallic carbon nanotube, for which 1) the valence and conduction bands of electrons with zero orbital angular momentum ($m=0$) coalesc at the two valley points ${bf{K}}$ and ${bf{K}}$ of the first Brillouin zone and 2) the energy spectrum of electrons with $m e 0$ has a gap whose size is proportional to $|m|$. Following adsorption of hydrogen atoms and application of an appropriately designed gate potential, electron energy levels in the CNT(QD) are tunable to have: 1) two-fold spin degeneracy; 2) two-fold isospin (valley) degeneracy; 3) three-fold orbital degeneracy $m=0,pm1$. As a result, an SU(12) Kondo effect is realized with remarkably high Kondo temperature. Unlike the SU(2) case, the low temperature conductance and magnetic susceptibility have a peak at finite temperature. Moreover, the magnetic susceptibilities for parallel and perpendicular magnetic fields (WRT the tube axis) display anisotropy with a universal ratio $chi_{rm{imp}}^parallel / chi_{rm{imp}}^perp=eta$ that depends only on the electrons orbital and spin $g$ factors.
Over-screened Kondo effect is feasible in carbon nanotube quantum dot junction hosting a spin $tfrac{1}{2}$ atom with single $s$-wave valence electron (e.g Au). The idea is to use the two valleys as two symmetry protected flavor quantum numbers $xi={
We investigate a tunable two-impurity Kondo system in a strongly correlated carbon nanotube double quantum dot, accessing the full range of charge regimes. In the regime where both dots contain an unpaired electron, the system approaches the two-impu
We calculate the conductance through a single quantum dot coupled to metallic leads, modeled by the spin 1/2 Anderson model. We adopt the finite-U extension of the noncrossing approximation method. Our results are in good agreement with exact numeric
The tunneling conductance is calculated as a function of the gate voltage in wide temperature range for the single quantum dot systems with Coulomb interaction. We assume that two orbitals are active for the tunneling process. We show that the Kondo
We examine the low energy behavior of a double quantum dot in a regime where spin and pseudospin excitations are degenerate. The individual quantum dots are described by Anderson impurity models with an on-site interaction $U$ which are capacitively