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Phases of the two-band model of spinless fermions in one dimension

Urs Ledermann, Karyn Le Hur

cond-mat.str-elarXiv:cond-mat/9910187

Abstract

We study the two-band model of spinless fermions in one dimension for weak repulsive interactions. In this case, the model is equivalent to the weakly interacting spinless two-leg ladder. We obtain analytic expressions for the superconducting pairing correlation function and the charge density correlation function, which show, that a finite interchain hopping tp results in dominant superconductivity for repulsive interactions (for vanishing tp, we recover previous results). We furthermore find that the transition from the superconducting phase to the usual one-dimensional (Luttinger) metal at large doping occurs via a mixed phase, where superconducting pairs are formed in the bonding band only. We give the phase diagram as a function of temperature and doping.

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