Fig. 2: Thickness dependence of critical temperature Tc and superconducting gap Δ.
From: The transition-metal-dichalcogenide family as a superconductor tuned by charge density wave strength
a Temperature evolution of the zero-bias tunneling conductance G0, normalized by its value in the normal state GN, of four representative junctions. Plotted in orange circles are the zero-bias points extracted from measured spectra. Plotted in blue dots are data measured while continuously cooling the samples from slightly above Tc down to base temperature. b BCS gap Δ vs. N. c Critical temperature Tc vs. N. Tc was taken to be the temperature at which the ratio G0/GN reaches 0.95. Overlaid in orange are data measured in transport devices by Refs. 4 and 17, exhibiting good agreement with our data. d Dependence of Δ/kB on Tc. The black line is a linear fit. In all panels, green plus-shaped markers indicate junctions whose thickness could not be directly observed in STEM and had to be estimated based on optical contrast. Error bars on N are ± 1 to reflect extra or missing layers that were not seen in cross-section imaging. Determination of the error bars on Tc and Δ is detailed in the Supplementary Information.
