Superconductivity and Topological Numbers in the Hubbard Chain with Bond-Charge Interaction
نویسندگان
چکیده
We determine the quantum phase diagram of the Hubbard chain with electron-hole symmetric correlated hopping at 1/2and 1/4-filling using geometric concepts and continuum limit field theory. The long distance behavior of various correlation functions show a very rich phase diagram with several insulating, metallic, and superconducting phases, which might be relevant to (TMTSF)2X compounds. The closing of charge and spin gaps are accurately resolved as topological transitions (jumps in π of Berry phases). The metallic or insulating character of each thermodynamic phase is obtained from the ground-state expectation value of a displacement operator in reciprocal space. PACS numbers: 71.10.+x, 3.65.Bz, 71.27.+a
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Superconductivity in an exactly solvable Hubbard model with bond-charge interaction.
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