The effect of hydrogen evolution reaction on conductance quantization of Au, Ag, Cu nanocontacts.

We have mechanically fabricated Au, Ag, and Cu nanocontacts in solution under electrochemical potential control. At the hydrogen evolution potential, fractional conductance peaks appeared near 0.5 G(0) (G(0) = 2e(2)/h) in the conductance histogram of Au and Cu. This fractional conductance peak was not observed in the conductance histogram of Ag. In the case of Au nanocontacts in 50 mM H(2)SO(4) solution, a 0.1 G(0) peak appeared in the conductance histogram, as well as the 0.5 G(0) peak. The origin of the fractional conductance peak and its metal dependence are discussed based on previously reported values of metal-hydrogen binding energy, which was estimated by the exchange current density for the hydrogen evolution reaction.