Antagonistic effects of nearest-neighbor repulsion on the superconducting pairing dynamics in the doped Mott insulator regime. / Reymbaut, A.; Charlebois, M.; Fellous Asiani, M.; Fratino, Lorenzo; Semon, P.; Sordi, Giovanni; Tremblay, A. -M. S.

In: Physical Review B, Vol. 94, No. 15, 155146, 27.10.2016, p. 1-14.

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Abstract

The nearest-neighbor superexchange-mediated mechanism for dx2−y2 superconductivity in the one-band Hubbard model faces the challenge that nearest-neighbor Coulomb repulsion can be larger than superexchange. To answer this question, we use cellular dynamical mean-field theory (CDMFT) with a continuous-time quantum Monte Carlo solver to determine the superconducting phase diagram as a function of temperature and doping for on-site repulsion U=9t and nearest-neighbor repulsion V=0,2t,4t. In the underdoped regime, V increases the CDMFT superconducting transition temperature Tdc even though it decreases the superconducting order parameter at low temperature for all dopings. However, in the overdoped regime V decreases Tdc. We gain insight into these paradoxical results through a detailed study of the frequency dependence of the anomalous spectral function, extracted at finite temperature via the MaxEntAux method for analytic continuation. A systematic study of dynamical positive and negative contributions to pairing reveals that even though V has a high-frequency depairing contribution, it also has a low frequency pairing contribution since it can reinforce superexchange through J=4t2/(U−V). Retardation is thus crucial to understanding pairing in doped Mott insulators, as suggested by previous zero-temperature studies. We also comment on the tendency to charge order for large V and on the persistence of d-wave superconductivity over extended-s or s+d wave.
Original languageEnglish
Article number155146
Pages (from-to)1-14
Number of pages14
JournalPhysical Review B
Volume94
Issue number15
DOIs
Publication statusPublished - 27 Oct 2016
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