Current shot noise in atomic contacts: Fe and FeH 2 between Au electrodes

Michael Mohr (1) , Alexander Weismann (1) , Dongzhe Li (2) , Mads Brandbyge (3) , Richard Berndt (1)

1 CAU - Christian-Albrechts-Universität zu Kiel = Christian-Albrechts University of Kiel = Université Christian-Albrechts de Kiel
2 CEMES - Centre d'élaboration de matériaux et d'études structurales
3 DTU - Danmarks Tekniske Universitet = Technical University of Denmark

Single Fe atoms on Au(111) surfaces were hydrogenated and dehydrogenated with the Au tip of a lowtemperature scanning tunneling microscope (STM). Fe and FeH 2 were contacted with the tip of the microscope and show distinctly different evolutions of the conductance with the tip-substrate distance. The current shot noise of these contacts has been measured and indicates a single relevant conductance channel with the spin-polarized transmission. For FeH 2 , the spin polarization reaches values up to 80% for low conductances and is reduced if the tip-surface distance is decreased. These observations are partially reproduced using density functional theory (DFT)-based transport calculations. We suggest that the quantum motion of the hydrogen atoms, which is not taken into account in our DFT modeling, may have a significant effect on the results.

Domaines: Physique [physics]

Michael Mohr, Alexander Weismann, Dongzhe Li, Mads Brandbyge, Richard Berndt. Current shot noise in atomic contacts: Fe and FeH 2 between Au electrodes. Physical Review B, 2021, 104 (11), pp.115431. ⟨10.1103/PhysRevB.104.115431⟩. ⟨hal-03746797⟩