Extended Data Fig. 1: Evidence of activated behavior.
From: Signatures of two gaps in the spin susceptibility of a cuprate superconductor
a-f: Knight shift (from which Kres has been subtracted) in vertical logarithmic scale vs. inverse temperature for the different doping levels. The straight line indicates exponential behaviour. g-l: same data vs. temperature. The nonlinear behaviour speaks against a power-law dependence. The p = 0.135 data undulates around the straight line (panel f) because of the larger difficulty in determining the exact line position for this sample: the line shapes are more complex due to ortho-III chain-oxygen order being both more complex and shorter ranged.
