Fig. 1 | Communications Physics

Fig. 1

From: Spectroscopy of the superconducting proximity effect in nanowires using integrated quantum dots

Fig. 1

Crystal phase engineered quantum dot in a superconductor - quantum dot - normal device. a False color scanning electron micrograph of the investigated device, consisting of a superconductor S (blue)–indium arsenide (InAs) nanowire (NW)–normal metal N (yellow) junction (scale bar: 100 nm). A quantum dot (QD, red) forms between two in-situ grown tunnel barriers (green) in the wurtzite phase. The distance between the QD and S is L ≈ 350 nm. The measurement scheme is shown schematically. The inset shows a high-resolution transmission electron micrograph of the atomically sharp zincblende/wurtzite interface of a comparable NW. b Schematic  energy diagram of such a system with an illustration of the proximity gap Δ* in the lead segment (LS), with a conductance GN in the normal and GS in the superconducting state. c Differential conductance G (e2/h) as a function of the backgate voltage VBG and the source-drain bias VSD in the superconducting state. The inset shows a single Coulomb blockade (CB) resonance in more detail. d CB diamonds at VBG exhibiting a gap in the transport characteristics

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