title: Gate-Controlled Superconducting Proximity Effect in Carbon Nanotubes.
abstract: The superconducting proximity effect in single-walled carbon nanotubes connected to niobium electrodes was controlled with the use of nearby gates that tune the niobium-nanotube transparency. At 4.2 kelvin, when the transparency was tuned to be high, a dip in the low-bias differential resistance was observed, indicating a proximity effect mediated by Andreev reflection. When the transparency was tuned to be low, signatures of Andreev reflection disappeared and only tunneling conduction was observed. Below approximately 4 kelvin, a narrow peak in differential resistance around zero bias appeared superimposed on the Andreev dip, probably as a result of electron-electron interaction competing with the proximity effect.
authors.affiliation: Department of Physics, Department of Chemistry, Stanford University, Stanford, CA 94305, USA.
authors.initials: AF
authors.lastname: Morpurgo
authors.initials: J
authors.lastname: Kong
authors.initials: CM
authors.lastname: Marcus
authors.initials: H
authors.lastname: Dai