Zero energy states at a normal-metal/cuprate-superconductor interface probed by shot noise

摘要

We report measurements of the current noise generated in the optimally doped, x = 0.15, Au-La-2_xSrxCuO4 junctions. For high transmission junctions on a (110) surface, we observed a split zero-bias conductance peak (ZBCP), accompanied by enhanced shot noise. We observed no enhanced noise neither in low-transmission junctions on a (110) surface nor in any junction on a (100) surface. We attribute the enhanced noise to Cooper parr transport through the junctions.