Effect of Adsorbed Helium on Electron Tunneling between Metal Electrodes

Abstract

The tunnel resistance of highly stable mechanically controlled break junctions of Al, Pt, Ag, and Au, recorded as a function of the electrode spacing, is found to be strongly influenced by the presence of adsorbed He atoms at low temperatures. Telegraph-noise-like resistance fluctuations of the tunnel resistance occur in a certain range of electrode separations when the measurements are performed in He gas at $T\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1.2$ K. Some models which may be capable of explaining the observed effects are discussed.