Reduction of Subgap Conductance of Tunnel Barriers
Original Publication Date: 1988-Jul-01
Included in the Prior Art Database: 2005-Feb-15
Subgap conductance of tunnel junctions in Josephson and three- terminal superconducting devices is decreased at high current densities by lowering the height of the insulating tunnel barrier. This is accomplished by introducing alkali ions at the barrier-superconductor interface. The addition of alkali ions, such as cesium, increases tunneling current and produces a more uniform barrier with lower subgap conductance. Increases in barrier thickness and current density reduce the RC time constant of the junction.