"Fidelity study of superconductivity in extended Hubbard models"

N. Plonka: C. J. Jia, Y. Wang, B. Moritz, and T. P. Devereaux; Physical review B, 07/08/15.

Additional Authors: C. J. Jia, Y. Wang, B. Moritz, and T. P. Devereaux

Abstract:

The Hubbard model with local on-site repulsion is generally thought to possess a superconducting ground state for appropriate parameters, but the effects of more realistic long-range Coulomb interactions have not been studied extensively. We study the influence of these interactions on superconductivity by including nearest- and next-nearest-neighbor extended Hubbard interactions in addition to the usual on-site terms. Utilizing numerical exact diagonalization, we analyze the signatures of superconductivity in the ground states through the fidelity metric of quantum information theory. We find that nearest and next-nearest neighbor interactions have thresholds above which they destabilize superconductivity regardless of whether they are attractive or repulsive, seemingly due to competing charge fluctuations.