Figure 2: Temperature dependence of the electrical resistivity of LaFeAsO1−xHx below 3 GPa and phase diagrams of LaFeAsO1−x(H, F)x.
From: Two-dome structure in electron-doped iron arsenide superconductors

(a–d) Temperature dependence of resistivity as a function of static pressure at x=0.08 (a), 0.21 (b), 0.30 (c) and 0.46 (d). The insets show pressure dependence of Tc. (e) Electronic phase diagram for LaFeAsO1−xHx (filled symbols) and LaFeAsO1−xFx (ref. 15; open symbols). The Tc under ambient (squares) and 3 GPa (inverted triangles) was determined from the intersection of the two extrapolated lines around superconducting transition and Ts (circles) was taken as the anomaly kink in the ρ–T curve7.