Anomalous Coulomb blockade in nanoconstricted quench-condensed Bi films

Nanobridges in thin 1-3 nm granular bismuth quench-condensed films with len gths and widths of 10 nm have been formed on top of an electrostatic gate m ade of oxidized aluminum. Periodic gate modulation of the Coulomb blockade- type I(V) curves of these nanoconstrictions has been observed in the temper ature range 4.2-11 K, indicating that the charge of a single grain controll ed the transport in the constriction. A reversible transition between two s tates with the same charging energy of 35 meV occurred at a temperature aro und 8 K, with up to 5 times enhanced conductivity at low temperatures. (C) 2000 Elsevier Science B.V. All rights reserved.