1 research outputs found
Antagonistic effects of nearest-neighbor repulsion on the superconducting pairing dynamics in the doped Mott insulator regime
The nearest-neighbor superexchange-mediated mechanism for d_{x^2-y^2}-wave
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
and nearest-neighbor repulsion . In the underdoped regime,
increases the CDMFT superconducting transition temperature even
though it decreases the superconducting order parameter at low temperature for
all dopings. However, decreases in the overdoped regime. 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 has a high-frequency depairing contribution, it also has a low
frequency pairing contribution since it can reinforce superexchange through
. Retardation is thus crucial to understand pairing in doped Mott
insulators, as suggested by previous zero-temperature studies. We also comment
on the tendency to charge order for large and on the persistence of d-wave
superconductivity over extended- or s+d-wave.Comment: Latex, 16 pages, 8 figure