Enhancing d-wave superconductivity with nearest-neighbor attraction in the extended Hubbard model

Mi Jiang

doi:10.1103/PhysRevB.105.024510

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Enhancing d-wave superconductivity with nearest-neighbor attraction in the extended Hubbard model

Mi Jiang

DOI 10.1103/PhysRevB.105.024510 · Physical Review B

T1

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Abstract

Motivated by the recent discovery of the anomalously nearest-neighbor attraction arising from the electron-phonon coupling, we quantitatively investigate the enhancing effects of this additional attractive channel on the d-wave superconductivity based on dynamic cluster quantum Monte Carlo calculations of a doped two-dimensional extended Hubbard model with nearest-neighbor attraction −V. Focusing on the range of 0<−V/t≤2, our simulations indicate that the dynamics of d-wave projected pairing interaction is attractive at all frequencies and increases with |V|. Moreover, turning on −V attraction enhances the (π,π) spin fluctuations but only enhances (suppresses) the charge fluctuations for small (large) momentum transfer. Thus, at V/t=−1 relevant to the “holon folding branch”, the charge fluctuations are insufficient to compete with the d-wave pairing interaction strengthened by enhanced spin fluctuations. Our work suggests the underlying rich interplay between the spin and charge fluctuations in giving rise to the superconducting properties.