Conductance fluctuations as a tool for investigating the quantum modes in atomic-size metallic contacts

Recently it has been observed that the conductance fluctuations of atomic-s ize gold contacts are suppressed when the conductance is equal to an intege r multiple of the conductance quantum. The fact that these contacts lend to consist exclusively of fully open or closed modes has been argued to be th e origin for this suppression. Here the experiments have been extended to a wide range of metallic elements with different chemical valences, and they provide information about the relation between the mode composition and st atistically preferred conductance values observed in conductance histograms .