2016/12/22 by Li, Shuaishuai, Xie, Yi-Qun, Hu, Yibin
#FOS: Physical sciences #Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
paper · doi:10.48550/arxiv.1612.07517
The low conductance of nickel atomic junctions in the hydrogen environment is studied using the nonequilibrium Green's function theory combined with first-principles calculations. The Ni junction bridged by a H2 molecule has a conductance of approximately 0.7 G0. This conductance is contributed by the anti-bonding state of the H2 molecule, which forms a bonding state with the 3d orbitals of the nearby Ni atoms. In contrast, the Ni junction bridged by the two single H atoms has a conductance of approximately 1 G0, which is weakly spin-polarized. The spin-up channels were found to contribute mostly to the conductance at a small junction gap, while the spin-down channels play a dominant role at a larger junction gap.