Fig. 4: Superconducting critical temperature Tc versus effective Fermi temperature TF for strongly correlated superconductors.
From: Fermi-liquid transport beyond the upper critical field in superconducting La2PrNi2O7 thin films
The dotted, dotted-dash, and dashed lines indicate Tc/TF = 0.01, 0.05, and 0.1, respectively. For the referenced materials, TF values are extracted assuming a quadratic energy dispersion \({E}_{{{{\rm{F}}}}}={\hslash }^{2}{k}_{{{{\rm{F}}}}}^{2}/(2{m}^{*})\) and using experimental data of effective mass and carrier density inferred from specific heat, Hall effect, and quantum oscillation measurements (refs. 21,22,23,24 and references therein) or from penetration depth measurements using \({E}_{{{{\rm{F}}}}}=({\hslash }^{2}/2){(3{\pi }^{2})}^{2/3}{n}_{{{{\rm{s}}}}}^{2/3}/{m}^{*}\) (ref. 57). The series of points in gradient blue illustrates the effect of hole doping on Tc and TF of La2−xSrxCuO4 (LSCO) with the darker colour indicating a higher doping level up to x = 0.21 (Tc = 27 K). Error bars for the cuprate materials indicate the variations in Tc and TF with carrier dopings, and for LPNO, the variations in TF inferred from the upper and lower limits of \({\bar{m}}^{*}\) estimates. MATBG magic-angle twisted bilayer graphene, TMTSF tetramethyltetraselenafulvalene, BEDT-TTF bisethylenedithiol-tetrathiafulvalene; Ba122: BaFe2(As1−xPx)2; STO: SrTiO3; YBCO: YBa2Cu3O6+x; Tl2201: Tl2Ba2CuO6+δ; Tl2223: Tl2Ba2Ca2Cu3O10+δ; Bi2223: Bi2Sr2Ca2Cu3O10+δ; Hg2223: Hg2Ba2Ca2Cu3O10+δ.
