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TT: Tiefe Temperaturen

TT 12: Correlated Electrons: Low-dimensional Systems - Models

TT 12.7: Vortrag

Dienstag, 28. März 2006, 11:15–11:30, HSZ 304

Hybridized mechanism of pairing of fermions in single-walled carbon nanotubes — •Igor Karnaukhov — Institute of Metal Physics, Vernadsky Street 36, 03142 Kiev, Ukraine

The discovery of high-temperature superconductivity in new exotic and perspective materials such as carbon nanotubes has greatly stimulated the investigation of new mechanisms of the superconductivity, the formulation of adequate low-dimensional models of strongly correlated electron systems. The remarkable electronic properties of single-walled carbon nanotubes (SWNT) are due to the special band structure, the most important peculiarity of the band structure is the crossing of two subbands near the Fermi level. The two-band fermion model with boundary fields describing the band structure of SWNT is proposed and solved exactly by means of the nested Bethe ansatz. The fermions in two subbands shifted one another interact via inner- and inter-band on-site Coulomb interactions, one-particle and correlated on-site hybridizations. It is shown that two component electron liquid state, one of which is defined by an attractive effective electron-electron interaction, is realized in the case of a strong hybridized interaction. The attractive interaction leads to the formation of spinless bound state of Cooper-type pairs and ’superconducting’ component of electron liquid. The strong boundary interaction leads to the formation of local spin-singlet boundary states, that induce the Mott-Hubbard metal-insulator phase transition (MIPT) in the chain. MIPT is realized at increasing of the magnetic field, fixing a gigantic magneto resistivity in the region of fields of the phase transition, and a gapless dielectric state - at critical boundary field.