STRONG TUNNELING IN THE SINGLE-ELECTRON TRANSISTOR

We have investigated the suppression of single-electron charging effec ts in metallic single-electron transistors when the conductance of the tunnel junctions becomes larger than the conductance quantum e(2)/h. We find that the Coulomb blockade of the conductance is progressively shifted at lower temperatures. The experimental results agree quantita tively with the available 1/T expansion at high temperature, and quali tatively with the predictions of an effective two-state model at low t emperature, which predicts at T = 0 a blockade of conductance for all gate voltages.