Antagonistic effects of nearest-neighbor repulsion on the superconducting pairing dynamics in the doped Mott insulator regime
| Autor: | M. Fellous Asiani, M. Charlebois, G. Sordi, Alexis Reymbaut, L. Fratino, Patrick Semon, Andre-Marie Tremblay |
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| Rok vydání: | 2016 |
| Předmět: |
Superconductivity
Physics Hubbard model Condensed matter physics Strongly Correlated Electrons (cond-mat.str-el) Condensed Matter - Superconductivity Mott insulator Quantum Monte Carlo Order (ring theory) FOS: Physical sciences Charge (physics) 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences 3. Good health Superconductivity (cond-mat.supr-con) Condensed Matter - Strongly Correlated Electrons Superexchange Pairing Quantum mechanics Condensed Matter::Superconductivity 0103 physical sciences Condensed Matter::Strongly Correlated Electrons 010306 general physics 0210 nano-technology |
| DOI: | 10.48550/arxiv.1607.02517 |
| Popis: | 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 $U=9t$ and nearest-neighbor repulsion $V=0,2t,4t$. In the underdoped regime, $V$ increases the CDMFT superconducting transition temperature $T_c^d$ even though it decreases the superconducting order parameter at low temperature for all dopings. However, $V$ decreases $T_c^d$ 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 $V$ has a high-frequency depairing contribution, it also has a low frequency pairing contribution since it can reinforce superexchange through $J=4t^2/(U-V)$. 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 $V$ and on the persistence of d-wave superconductivity over extended-$s$ or s+d-wave. Comment: Latex, 16 pages, 8 figures |
| Databáze: | OpenAIRE |
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