SU(12) Kondo Effect in Carbon Nanotube Quantum Dot

Abstract

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 $\mathbf{K}$ and ${\mathbf{K}}^{\prime }$ of the first Brillouin zone and 2) the energy spectrum of electrons with $m\ne 0$ 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 $m=0,\pm 1$. 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 ${\chi }_{\mathrm{imp}}^{\parallel }/{\chi }_{\mathrm{imp}}^{\perp }=\eta$ that depends only on the electron's orbital and spin $g$ factors.

18 pages, 11 figures, discussions expanded, Appendix extended, references added

References in corpus (11)

• Orbital Kondo effect in carbon nanotubes
• Kondo Quantum Criticality of Magnetic Adatoms in Graphene
• SU(4) and SU(2) Kondo Effects in Carbon Nanotube Quantum Dots
• Magnetically Tunable Kondo - Aharonov-Bohm Effect in a Triangular Quantum Dot
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• Superlattices Consisting of "Lines" of Adsorbed Hydrogen Atom Pairs on Graphene
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• Tunneling through triple quantum dots with mirror symmetry
• Kondo effect in systems with dynamical symmetries
• First-principles study of bandgap effects in graphene due to hydrogen adsorption
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• Thermoelectric Transport through SU(N) Kondo Impurity
• Nonlinear Seebeck effect of SU($N$) Kondo impurity
• Poor man's scaling: anisotropic Kondo and Coqblin--Schrieffer models
• Effects of strong electron interactions and resonance scattering on power output of nano-devices
• Poor man's scaling: $XYZ$ Coqblin--Schrieffer model revisited
• Thermoelectric transport and current noise through a multilevel Anderson impurity: Three-body Fermi-liquid corrections in quantum dots and magnetic alloys
• The role of spin-flip assisted or orbital mixing tunneling on transport through strongly correlated multilevel quantum dot
• Fractional shot noise of an SU(N) Kondo system