Eur. Phys. J. B 8, 497-505 (1999)
https://doi.org/10.1007/s100510050717

Electronic and magnetic structure of the undoped two and three-leg ladder cuprates in an itinerant electrons model

¹ Laboratoire Surfaces et Supraconducteurs, École Supérieure de Physique et Chimie Industrielles de la ville de Paris, 10 rue Vauquelin, 75231 Paris Cedex 5, France
² Groupe de Physique des Milieux Denses, UFR Sciences - Université Paris XII, 61 avenue du Général de Gaulle, 94010 Créteil Cedex, France

Received: 3 June 1998
Published online: 15 April 1999

Abstract

We study the electronic and magnetic structure of the undoped ideal two and three-leg ladder cuprates by assuming a moderate on site coulombic repulsion. This analysis is an extension of the Fermi liquids studies proposed for the CuO₂ plane in view to explain the high T_c superconductivity and the competition with the antiferromagnetic phase. At zero doping, the quasi-one-dimensionality of the structure results in SDW correlations with different (commensurate) vectors according to the number of legs, which contrasts with the predictions made from the Heisenberg model. At mean field, and for n = 3 (Sr₂Cu₃O₅), we predict a magnetic ordered state, detected by μSr and NMR measurements with critical temperatures consistent with our assumptions on the physical parameters, the modulation vector being . The presence of several bands at the Fermi level explains why there is no observable gap in the static susceptibility measurements. For n = 2, we predict a gap consistent with experimental Curie susceptibility. But the expected magnetic instability is detected only in La₂Cu₂O₅, where the interladder coupling is stronger. In every case the one-dimensional van Hove singularities are far from the Fermi level, making difficult the obtaining of high T_c superconductivity.