| Abstract: | In order to unravel some of the complexity of the cuprate superconductors we applied small perturbations to these materials and checked their response. The first perturbation was in the cations charge distribution in the unit cell. We changed it while keeping the total charge constant, and measured the holes density in the CuO2 plane using nuclear magnetic resonance. The second perturbation was oxygen isotope substitution: We replaced Oxygen 16 by Oxygen 18 and examined how the critical temperatures vary using muon spin rotation. In both cases it was found that the holes density in the plane does not reflect the holes distribution in the unit cell, and that a plane doping efficiency parameter must be introduced. This simple effect can be easily misinterpreted as an exotic mechanism which affects the transition temperatures. |
