title: SU(4) Kondo effect in carbon nanotubes.
abstract: We investigate theoretically the nonequilibrium transport properties of carbon nanotube quantum dots. Owing to the two-dimensional band structure of graphene, a double orbital degeneracy plays the role of a pseudospin, which is entangled with the spin. Quantum fluctuations between these 4 degrees of freedom result in an SU(4) Kondo effect at low temperatures. This exotic Kondo effect manifests as a four-peak splitting in the nonlinear conductance when an axial magnetic field is applied.
authors.affiliation: Department of Physics, Korea University, Seoul 136-701, Korea.
authors.forename: Manh-Soo
authors.initials: MS
authors.lastname: Choi
authors.forename: Rosa
authors.initials: R
authors.lastname: López
authors.forename: Ramón
authors.initials: R
authors.lastname: Aguado