Figure 1
From: Classifying superconductivity in Moiré graphene superlattices
The upper critical field data, Bc2,⊥(T), for sample M1 (θ = 1.16°) of measured by Cao et al.7 (squares) fitted to single band models. (a) red: fit to Gorter-Casimir (GC) two fluid model (Eq. 1) with a goodness of fit R = 0.9892 (Tc = 0.489 ± 0.004 K, Bc2,⊥(0) = 81 ± 2 mT, ξab(0) = 64 ± 1 nm); yellow: Werthamer-Helfand-Hohenberg (WHH) model (Eq. 2), R = 0.9976 (Tc = 0.505 ± 0.005 K, Bc2,⊥(0) = 81 ± 2 mT, ξab(0) = 64 ± 1 nm). (b) Baumgartner-WHH (B-WHH) model (Eq. 3 and 4), R = 0.9966 (Tc = 0.497 ± 0.003 K, Bc2,⊥(0) = 92 ± 1 mT, ξab(0) = 60 ± 1 nm). (c) Jones-Hulm-Chandrasekhar (JHC) model Eq. 5, R = 0.9930 (Tc = 0.515 ± 0.005 K, Bc2,⊥(0) = 97 ± 2 mT, ξab(0) = 58 ± 1 nm). (d) Gor’kov model Eq. 7, R = 0.9959 (Tc = 0.494 ± 0.003 K, Bc2,⊥(0) = 86 ± 1 mT, ξab(0) = 62 ± 1 nm). (e) Model proposed in ref. 24, R = 0.9979 (Tc = 0.504 ± 0.007 K, Bc2,⊥(0) = 80 ± 2 mT, ξab(0) = 64 ± 1 nm, Δ(0) = 81 ± 6 meV, ΔC/C = 1.46 ± 0.28, 2Δ(0)/kBTc = 3.73 ± 0.28).
