Fig. 2: Low-temperature characterisation of hybrid superconducting/molecular/metal heterostructures.
From: Spin-singlet to triplet Cooper pair converter interface
a A schematic showing the fabricated sample which is grown alongside a control Nb film. b The dependence upon the superconducting transition temperature (Tc) suppression with C60 thickness for Nb(50 nm)/C60(t)/Au(20 nm)/Al(2 nm) stacks for continuous (blue symbols) and discontinuous (red symbols) C60 films. The modification of the superconducting gap energy via the inverse proximity effect is greatest for the sample without C60. As a fullerene barrier layer is introduced, and its thickness increased, the Tc never fully recovers to its pristine value. Therefore, there is a leakage of Cooper pair states into the C60 and through to the Au, where an effective length scale for the propagation of Cooper pairs is \({\upxi}_{{\mathrm{Eff}}}\) = 30 ± 8 nm. A y-axis line-break allows the data point obtained for the sample with a discontinuous island-like C60 barrier to be shown. Error bars are uncertainties in the critical temperature measurement. For each point, the Tc suppression is obtained via low-temperature transport measurements, such as those shown in (c; grey symbols are for the control samples).
