We study the interaction effects on the ground state of nanographite ribbons with zigzag edges. Within the mean-field approximation, we find that there are two possible phases: the singlet superconducting (SS) phase and the excitonic insulator (EI) phase. The two phases are separated by a first-order transition point. After taking into account the low-lying fluctuations around the mean-field solutions, the SS phase becomes a spin liquid phase with one gapless charge mode. On the other hand, all excitations in the EI phase, especially the spin excitations, are gapped.
|Number of pages||6|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2002 Jan 1|
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics