Fidelity study of superconductivity in extended Hubbard models

N. Plonka, C. J. Jia, Y. Wang, B. Moritz, and T. P. Devereaux

Phys. Rev. B 92, 024503 – Published 8 July 2015

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.

Received 8 May 2015

DOI:https://doi.org/10.1103/PhysRevB.92.024503

Authors & Affiliations

N. Plonka^1,2,*, C. J. Jia^1,2, Y. Wang^1,2, B. Moritz^2,3, and T. P. Devereaux^2,4,†

¹Department of Applied Physics, Stanford University, Stanford, California 94305, USA
²Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
³Department of Physics and Astrophysics, University of North Dakota, Grand Forks, North Dakota 58202, USA
⁴Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA

^*nachumplonka@gmail.com
^†tpd@slac.stanford.edu

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Vol. 92, Iss. 2 — 1 July 2015

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