Figure 1

(a) Single STM spectrum (red) representative of the average ${\Delta }_s$ and ${\Delta }_L$ and a spatially averaged STM spectrum (black) from a 240 Å $dI/dV$ map. (a),(b),(c),(d) and (h) show data on 0.4La samples. (b) Symmetrized ARPES energy distribution curves (EDCs) taken at antinodal position and at the arc tip ($\theta \sim 21°$) (see inset to Fig. 2d for definition of $\theta$). (c) Gap histogram (237 Å $dI/dV$ map) with average ${\Delta }_s$ at $10.50\mathrm{meV}\pm 2.8\mathrm{meV}$ and ${\Delta }_L$ average at $27.2\mathrm{meV}\pm 5.4\mathrm{meV}$. (d) Spectra along a 100 Å line. (e),(f), and (g) Similar data as (a),(b), and (c) but for the 0.1La samples. Arc tip angle $\theta \sim 18°$. Average ${\Delta }_s$ is $7.4\mathrm{meV}\pm 1.6\mathrm{meV}$ and average ${\Delta }_L$ is $20.7\mathrm{meV}\pm 3.9\mathrm{meV}$. (h) Spectra from a 240 Å map sorted and averaged on the basis of ${\Delta }_L$.Reuse & Permissions

Figure 2

(a) ARPES spectra showing momentum ($k$) dependence of EDCs of 0.4La sample. (b) Temperature dependence of symmetrized EDCs for 0.4La sample at antinode. Dotted line is a guide to the eye to show the large pseudogap above $T_c$. (c) Same as (b) for 0.1La sample (d) $k$-dependent gap value $Vs$ Fermi surface angle (defined in the inset) for data shown in (a), extracted by locating the coherence peak position (dots), a feasible method only up to the coherence arc tip, and by the position of the slope change thereafter (squares). (e) Division of antinodal 5 K EDC by 40 K EDC for 0.4La sample reveals coherence peaks that mask the larger gap. (f) Schematic of gap $Vs$ angle showing the previously proposed two gap picture (solid lines) and our new proposal (solid plus dotted lines) based on the STM and ARPES data.Reuse & Permissions

Figure 3

(a) 160 Å $dI/dV$ map [$g(r,E)$] of 0.4La sample at energy $(E)=+7\mathrm{meV}$. Inset shows simultaneous topography. (b) 160 Å $g(r,E)$ map of 0.1La sample at $E=-11\mathrm{meV}$. (c) Fourier transform of map in (a) showing the $q$ vectors arising from the CDW pattern. The unit for the axis is $2\pi /a_0$ where lattice constant $a_0=3.83\AA$. (d) Fourier transform of map in (b). (e) ARPES Fermi surface mapping of 0.4La sample. The inset shows the nesting vector at the arc tip which matches the average STM periodicity. (f) ARPES Fermi surface mapping of 0.1La sample showing the now smaller $q$ vector.Reuse & Permissions

Figure 4

(a) 237 Å $g(r,E)$ map at $E=0\mathrm{meV}$, showing the position of the two line cuts used to illustrate contrast reversal. Shown below the map, are smoothed linecuts from simultaneously obtained maps at $E=+50\mathrm{meV}$ and $-50\mathrm{meV}$. (b) Scatter plot of occurrences of ${\Delta }_s$ and ${\Delta }_L$ for the data plotted in Fig. 1c (0.4La, blue squares) and Fig. 1g (0.1La, red squares). The inset shows the spatial dependence of the cross correlation between the ${\Delta }_s$ and ${\Delta }_L$ maps which retains a finite value up to a few lattice constants.Reuse & Permissions