Impurity effects on the flux phase quantum-critical-point scenario
Max-Planck-Institut für Festkörperforschung
Heisenbergstr. 1, 70569 Stuttgart, Germany
Accepted: 7 December 1999
Impurity substitution of Zn in La-214 and (Y, Ca)-123 high- superconductors suppresses but does not affect appreciably the onset of the pseudogap phase in the underdoped region nor optimal doping or the position of the inferred quantum critical point. Based on a 1/N expansion of the t-J model we explain these findings as well as the similar dependence on a magnetic field in terms of a quantum-critical-point scenario where a flux phase causes the pseudogap.
PACS: 74.10.+v – Occurrence, potential candidates / 74.25.Dw – Superconductivity phase diagrams / 74.20.Mn – Nonconventional mechanisms (spin fluctuations, polarons and bipolarons, resonating valence band model, anyon mechanism, marginal Fermi liquid, Luttinger liquid, etc.)
© EDP Sciences, 2000