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Prochain séminaire LANEF/Matériaux Quantiques :


Jeudi 11 janvier 2024 à 14h00

Benjamin Bacq  (Institut Quantique, Université de Sherbrooke)

“ Towards predictive ab initio methods for unconventional superconductivity: a study of multilayer cuprates “




Pour accéder à ce séminaire :

Institut Néel CNRS, Bâtiment K, Salle Rémy Lemaire  (K223)


Résumé : High-temperature n-layer cuprate superconductors have the remarkable universal feature that the maximum transition temperature TC is always obtained for the tri-layer compound. It remains unclear how the recent breakthroughs, highlighting the relation of the charge transfer gap (CTG) and the spin-exchange J with the pairing density, can be related to this universality. By integrating an exact diagonalization solver to a density functional theory (DFT) plus cluster dynamical mean-field theory (CDMFT) framework, we were able to carry charge self-consistent DFT+CDMFT calculations for n=1-5 multilayer cuprates. Remarkably, the undoped compounds already host a peculiar behavior as a function of n: the CTG first decreases until reaching a minimum at n=3, and then stabilizes. The CTG is smaller in the inner CuO2 planes, and consequently the spin exchange J is larger as compared to the outer planes, which corroborates the experimental evidence of stronger antiferromagnetic spin fluctuations in the inner planes. Upon hole-doping, the charge carriers are inhomogeneously distributed among the different CuO2 planes, which leads to the coexistence of Fermi pockets and arcs in the Fermi surface as observed in experiments. Our work paves the way towards ab initio material-specific predictions of the superconducting order parameter

Les organisatrices :

Elsa Lhotel (elsa.lhotel@neel.cnrs.fr)
Florence Levy-Bertrand (florence.levy-bertrand@neel.cnrs.fr)