Superconducting phases in a generalized Hubbard chain with additional off-diagonal hopping processes

Abstract

Applying the bosonization and renormalization group techniques, we study a generalized Hubbard chain incorporating extra off-diagonal hopping processes in the weak regime, and determine rich ground-state phase diagrams. At half filling, in addition to the insulating phases (HI, MI and DI), there exist the superconducting phases (LE and LL). The off-diagonal hopping accounts for the occurrence of insulator–superconductor transition. Away from half filling, the transition from the LL to LE phase takes place, and the insulating phases disappear. The result provides an insignificant insight into unconventional scenarios for Cooper pairing and insulator-superconductor transition.