Critical doping in overdoped high-Tc superconductors - a Quantum Critical Point?

Abstract

Evidence is presented from the scaling of the Knight shift, entropy and transport properties together with the sharp peaking of condensation energy, critical currents, superfluid density and a variety of other physical properties for the occurrence of a common critical doping point in lightly overdoped high-Tc superconductors (HTS). This critical doping lies at the point where the doping-dependent normal-state pseudogap energy, Eg, falls to zero and bears a strong, though incomplete, resemblance to a quantum critical point (QCP). A QCP scenario could lead directly to an explanation of the non-Fermi liquid behaviour of the normal-state metallic phase and the overall generic behaviour of the HTSC.