Insulator With Magnetic Impurities for Suppressing Josephson Currents
Original Publication Date: 1984-Nov-01
Included in the Prior Art Database: 2005-Feb-05
In a cryogenic tunneling transistor consisting of a sandwich-like structure of three electrodes separated by two insulating layers that permit tunneling, the insulating layers are doped with magnetic impurities in order to suppress Josephson currents which may otherwise couple the electrodes. Fig. 1 schematically illustrates the three-port structure. Fig. 2 represents the energy band diagram of the device. Two insulating layers I are arranged between source S and gate G electrodes and between gate and drain D electrodes, respectively. Source/drain voltage VSD is provided to electrodes S and D, whereas the signals VG for controlling the tunnel current through the device are applied to electrode G. Control is by lowering or increasing the height of the tunnel barrier (in the order of a few meV) between S and D.