Figure 1

. The schematic of the experimental setup. A Schwarzschild objective focuses the high brilliance synchrotron beam to a submicron spot onto the sample and the photoemitted electrons are energy analyzed with a hemispherical electron energy analyzer and a position sensitive detector. The sample stage is manipulated with piezo drives to scan the sample surface. A continuous helium flow cryostat allows the sample temperature to be varied between approximately 40 and 300 K. The total intensity from each spot can be mapped to provide a microscopic view of the sample surface that includes contributions from the topography as well as variations in the electronic structure. Taking the ratio of the intensities at two different energies and plotting the ratio instead of the absolute intensity in order to accentuate only the changes in the electronic structure can largely eliminate topographic features.Reuse & Permissions

Figure 2

. (a) Spectral changes close to the Fermi energy across the metal-insulator transition, exhibiting a finite density of states at $E_F$ in the metallic phase. The inset shows the overall spectral feature over a wide energy range. (b) Superposition of valence band spectra consisting of mainly Mn $3d$ and O $2p$ states recorded with a high spatial resolution ($0.5\mu \mathrm{m}$) at 28 different spots on the sample. (c) Superposition of the shallow core level spectra from La, Pr and Ca after a linear background subtraction from the same set of spots as in panel (b).Reuse & Permissions

Figure 3

. Spectromicroscopic images over $\sim 54\times 25\mu {\mathrm{m}}^{\mathrm{2}}$ areas of the sample surface. The top two rows show images from one region of the sample and the bottom row from another part, with the first panel in each of the two sets represented by gray scale being a topographic image and the rest ratio images. Ratio images at the lowest temperature for each image show emergence of distinct insulating patches (red-yellow) deep within the metallic regime (blue-green), which exhibit memory effects in the formation and morphology on temperature cycling. The color contrast in the ratio images vanishes and the entire sample transforms into the insulating phase as the temperature is increased, converting the system into an electronically homogeneous phase.Reuse & Permissions