Superconductivity in ultrathin artificial cuprate structures

Layer-by-layer pulsed-laser deposition has been used to grow ultrathin supe rconducting (Ba0.9Nd0.1)CuO2+x/CaCuO2 artificial structures with various th icknesses of the two constituent layers. Superconductivity was observed in the ultrathin structure consisting of a single CaCuO2 superconducting block sandwiched between two (Ba0.9Nd0.1)CuO2+x blocks. The results obtained all owed an experimental demonstration of the currently accepted structural mod el for high T-C superconductivity, which requires the presence in the same structure of two blocks with different functional properties: the supercond ucting infinite layer block and the nonsuperconducting charge reservoir blo ck. (C) 2001 American Institute of Physics.