Current shot noise in atomic contacts: Fe and FeH2 between Au electrodes

The shot noise of the current through an iron atom on gold and through FeH${}₂$ is measured and calculated. The authors find hydrogen to substantially increase the spin polarization up to values of about 80%. The data suggest that the quantum motion of hydrogen and the associated zero-point energy, which are not described by the density functional theory modeling here, may play an important role.