The stripe critical point for cuprates

The experimental determination of the quantum critical point (QCP) that triggers the self-organization of charged striped domains in cuprate perovskites is reported. The phase diagram of duped cuprate superconductors is determined by a first variable, the hole doping delta, and a second variable, the micro-strain epsilon of the Cu-O bond length. obtained from the Cu K-edge extended x-ray absorption fine structure. For a fixed optimum doping, delta (c) = 0.16, we show the presence of the QCP for the onset of local lattice distortions and stripe formation at the critical micro-strain epsilon (c). The critical temperature T-c(epsilon, delta) reaches its maximum at the quantum critical point (epsilon (c), delta (c)) for the formation of bubbles of superconducting stripes. The critical charge, orbital and spin fluctuations near this strain QCP provide the interaction for the pairing.