ELECTRONS WITH CORRELATED HOPPING INTERACTION IN ONE-DIMENSION

The 1D system of correlated electrons characterized in addition to the usual on-site (U) and nearest-neighbour (V) repulsion by a correlated -hopping term (t) is considered. The ground state phase diagram is st udied within the framework of the weak-coupling continuum-limit approa ch. At filling nu the effective interaction originating from the corre lated-hopping term which appears in the continuum-limit theory is give n by tcos(pinu). Being repulsive for nu < 1/2 and attractive for nu > 1/2, this interaction leads to a characteristic band-filling dependen ce of the phase diagram of the system. For nu not-equal 1/2, depending on the relation between the bare values of the coupling constants (U, V, tcos(pinu)) and, hence, on the band-filling, the system shows thr ee different phases in the infrared limit: a Luttinger metal, a nonmag netic metal and a singlet superconducting phase. For nu = 1/2, the cor related-hopping interaction is dynamically trivial, leading only to a renormalization of the one-electron hopping amplitude and the phase di agram of the model coincides with that of the extended Hubbard model.