Extended Data Fig. 3: Extracting Tc and T* from temperature-dependent resistance of monolayer Bi-2212.
From: High-temperature superconductivity in monolayer Bi2Sr2CaCu2O8+δ
a, Illustration of Tc and T* extraction from temperature-dependent resistance (black curve, which mostly overlaps with the red curve) and its derivative (blue curve). We used two definitions of Tc in our analysis: (i) Tc,diff where the slope of resistance vs temperature curve is maximum70; (ii) Tc0 from fitting with Aslamasov–Larkin paraconductivity model71 \(\varDelta \sigma =\sigma (T)-{\sigma }_{{\rm{normal}}}(T)=a{(T/{T}_{{\rm{c}}0}-1)}^{-1}\). Near optimal doping, \({\sigma }_{{\rm{normal}}}(T)={(bT+c)}^{-1}\), so Tc0 can be extracted from fitting with \(R(T)=(bT+c)(T-{T}_{{\rm{c}}0})/(T-{T}_{{\rm{c0}}}+a)\) (red curve). T* is determined as the temperature at which the derivative of temperature-dependent resistance deviates from constant value (broken blue line; ref. 72). b, c, \({T}_{c,\mathrm{diff}}^{{\rm{\max }}}\) (b) and \({T}_{{\rm{c}}0}^{{\rm{\max }}}\) (c) of monolayer and bulk Bi-2212. Bulk data were obtained from optimally doped crystals (OP88). Under both definitions, the highest maximum Tc of monolayers is within the statistical uncertainty range of the Tc in optimally doped bulk crystals.
