Can photoemission accurately probe the bulk electronic structure of the complex oxides?

Authors

Jaewu Choi, University of Nebraska-LincolnFollow
C. Waldfried, University of Nebraska-Lincoln
Sy_Hwang Liou, University of Nebraska-LincolnFollow
Peter A. Dowben, University of Nebraska-LincolnFollow

Date of this Version

9-1-1998

Comments

Published in J. Vac. Sci. Technol. A 16„5…, Sep/Oct 1998. ©1998 American Vacuum Society. Permission to use. http://scitation.aip.org/jvsta/.

Abstract

The surface of the complex oxides, in particular the manganese perovskites, is dominated by a different free enthalpy at the surface. This can be demonstrated by surface segregation after annealing the samples. By comparing relative x-ray photoelectron spectroscopy intensities of the manganese perovskite La_1-xCa_xMnO₃ (x=0.1, 0.35) for different emission angles, the profile of elemental concentration was determined. Analysis shows evidence for pronounced surface segregation of calcium. Our results suggest that there are strong differences between surface and bulk enthalpies without segregation or surface relaxation. This is consistent with the previously observed surface resonance in the electronic band structure.