Probing the Conduction Channels of Gold Atomic-Size Contacts: Proximity Effect and Multiple Andreev Reflections
We have investigated the electronic transport properties of Au quantum point contacts fabricated by the mechanically controllable breakjunction technique using non-linearities in the current-voltage characteristics induced by the proximity effect (PE) of superconducting aluminum electrodes. The PE shows up also in an hysteretic transition to the normal state when applying an external magnetic field. We find that the very smallest contact formed by a single atom between the electrodes contributes one channel to the transport as predicted by different theoretical models. The analysis of the transport channels of retraceable opening and closing procedures gives additional evidence that the transport channels are determined by the properties of the central atom.
KeywordsCentral Atom Conduction Channel Single Conduction Channel Tunnel Regime Contact Regime
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