Figure 1

(Color online) (a) Raman spectra of ${}^{16}\text{O}$ (blue or black) and ${}^{18}\text{O}$ (red or gray) Ln-Bi2201 samples. (b) Energy-momentum dispersions along the nodal direction both for ${}^{16}\text{O}$ (left) and ${}^{18}\text{O}$ (right) from the least-disordered La-Bi2201 (blue or black) and most-disordered Gd-Bi2201 (red or gray). (c) Momentum-space mapping of the spectral weight of La-Bi2201. (d) Intensity plot of ARPES data as a function of the binding energy and momentum along the nodal direction. (e) Real parts of the self-energy of La-Bi2201 for both ${}^{16}\text{O}$ (blue or black line) and ${}^{18}\text{O}$ (red or gray line).Reuse & Permissions

Figure 2

(Color online) [(a) and (b)] Momentum-space mapping of spectral weight of the normal La-Bi2201 (La16) and the oxygen-isotope-substituted La-Bi2201 (La18), respectively. Note that the respective directions of $k_x$ and $k_y$ correspond to those of $\Gamma \text{-Y}$ and $\Gamma \text{-X}$. (c) Fermi surfaces extracted by the MDC method with La16 and La18 shown in blue (or black) and red (or gray), respectively. [(d)–(f), (g-i), and (j-l)] Same as in panels, with the exception that Ln is substituted with Nd, Eu, and Gd, respectively.Reuse & Permissions

Figure 3

(Color online) (a) Temperature dependence of the magnetic susceptibility normalized to the value at 5 K for ${}^{16}\text{O}$ [blue (solid) marks] and ${}^{18}\text{O}$ [red (open) marks] pairs in disorder-controlled Ln-B2201, where $\text{Ln}=\text{La}$, Nd, Eu, and Gd. Disorder dependence of $T_c$ and the decrease in $T_c$ caused by oxygen isotope substitution $\left(\Delta T_c\right)$ are shown in the inset. (b) Disorder dependence of ${\alpha }_{T_c}$. Open (red) circle shows the results for nearly optimally doped ${\text{Bi}}_2{\text{Sr}}_{1.6}{\text{La}}_{0.4}{\text{CuO}}_{6+\delta }$ by Chen et al. (Ref. 8). (c) Universal function relation between the pair-breaking parameter and the reduced $T_c$ for ${}^{16}\text{O}$ (solid curve) and ${}^{18}\text{O}$ (broken curve). Disorder dependence of $\widetilde{{\Delta }_0}$ [black (closed) circles], ${\tilde{E}}_{PG}$ [red (open) circles], and $\widetilde{T_c}$ [blue crosses], which are normalized by those of La-Bi2201, are shown in the inset. Superconducting gaps at the absolute zero point, ${\Delta }_0\left(0\right)$, are estimated from those at the finite temperature reported in previous ARPES studies (Refs. 21, 36) on the basis of ${\Delta }_0\left(T\right)={\Delta }_0\left(0\right)\text{tanh}(\sqrt{\gamma }\sqrt{1-T/T_c}/\text{tanh}\left(\sqrt{\gamma }\right)\phantom{)}$, where $\gamma =3.5$. The pseudogaps are estimated from the superconducting gaps by Harada et al. (Ref. 35).Reuse & Permissions