Superconducting dome and pseudogap endpoint in Bi2201

Once doped away from their parent Mott insulating state, the hole-doped cuprates enter into many varied and exotic phases. The onset temperature of each phase is then plotted versus $p$---the number holes per copper atom---to form a representative diagram. Apart differences in absolute scales among various families, resultant diagrams are strikingly similar. In particular, $p$ values corresponding to optimal doping (${p}^{\mathrm{opt}}\ensuremath{\sim}0.16$) end pseudogap $({p}^{*}\ensuremath{\sim}0.19--0.20)$ essentially same for all cuprate families bar one: single-layer Bi-based ${\mathrm{Bi}}_{2+z\ensuremath{-}y}{\mathrm{Pb}}_{y}{\mathrm{Sr}}_{2\ensuremath{-}x\ensuremath{-}z}{\mathrm{La}}_{x}{\mathrm{CuO}}_{6+\ensuremath{\delta}}$ (Bi2201). This anomaly arises partly due complex stoichiometry this material also different inferred disparate (e.g., bulk or surface) measurements performed on samples with comparable superconducting transition temperatures ${T}_{c}$. Here, by combining in-plane resistivity zero high magnetic fields angle-resolved photoemission spectroscopy studies normal we argue that diagram Bi2201 may fact be similar realized other families. study therefore brings fold supports notion universality ${p}^{\mathrm{opt}}$ ${p}^{*}$ cuprates.