Seminars Archive

X-Ray Microscopy of strongly correlated system

Abstract
The electronic structure of high-temperature superconducting {Ba(1-x)K(x)BiO3, La(2-x)Sr(x)CuO4, Bi2212} and giant magnetoresistance {La(1-x)Sr(x)MnO3} single crystals has been studied using a scanning photoelectron microscope with a lateral resolution in the one micrometer range. The crystals were cleaved by fracturing in situ and were kept cooled (~100K) during cleavage and measurements. It has been shown that for all compounds studied it is possible to change the oxygen content and convert the surface from the metallic to the dielectric state. The electronic states close to the Fermi level after such a treatment show a different doping dependence as compared to the case of cation doping. By imaging the surface on the micrometer scale we find significant variations in the valence band intensity and density of states close to the Fermi level over the surface. The possibility of utilizing the photoelectron microscope to study phase separation in strongly correlated systems is discussed.