To the theory of current transport in the mechanically controllable break junctions

Abstract

The transport mechanisms for metal–molecule–metal junction after break are analyzed. Theoretical expression for the threshold voltage for transmission from the direct tunneling current to the Fowler–Nordheim tunneling is obtained and analyzed. It is show that threshold voltage depends on the electrode metal work function and displacement. With the increase in displacement the threshold voltage quickly decreases. Differential resistances for the low and high voltage modes increase with increasing in the displacement, and in the Fowler–Nordheim tunneling mode the differential resistance increases when voltage is decrease. It is shown that for the cases commonly used metals (Ag, Au, Pt) the threshold voltage is linearly dependent on the work function of metals.