2016 CAP Congress / Congrès de l'ACP 2016

Antagonistic effects of nearest-neighbor repulsion on the pairing dynamics of the extended Hubbard model

16 Jun 2016, 08:45

15m

SITE G0103 (University of Ottawa)

Oral (Non-Student) / orale (non-étudiant) Condensed Matter and Materials Physics / Physique de la matière condensée et matériaux (DCMMP-DPMCM) R1-2 Strongly Correlated Systems (DCMMP) / Systèmes fortement corrélés (DPMCM)

Speaker

Dr Alexis Reymbaut (Université de Sherbrooke)

Description

While most experimental and theoretical clues lean towards a magnetic origin for the pairing mechanism of cuprates, the question of its degree of retardation in the strong correlation regime remains highly controversial.[1,2] The answer to this question lies partly in the frequency dependence of the anomalous spectral function of doped Mott insulators, extracted at finite temperature via the MaxEntAux method [3] for analytic continuation. Using Cellular Dynamical Mean-Field Theory for the Hubbard model with nearest-neighbor repulsion $V$, we show that this repulsion has antagonistic effects on the critical temperature $T_c$ as it boosts $T_c$ at low doping but diminishes it at large doping. The study of pair-breaking and pair-forming contributions to superconductivity clarifies the nature of these effects. They emerge from a compromise between the trivial Coulomb pair-breaking effect of $V$ and a more subtle pair-forming effect of $V$. The latter arises from the strengthening of short-ranged antiferromagnetism through the coupling constant $J=4t^2/(U-V)$ where $U$ is the on-site Hubbard interaction, and $t$ the hopping amplitude. [1] P.W. Anderson, Science **316**, 1705 (2007). [2] D.J. Scalapino, e-letter response to Science **316**, 1705 (2007). [3] A. Reymbaut, D. Bergeron and A.-M.S. Tremblay, Phys. Rev. B **92**, 060509(R) (2015)