Inverse photoemission studies of the empty electronic states and surface stability of La/sub 1. 85/Sr/sub 0. 15/CuO/sub 4/

Journal Article · Tue Sep 01 04:00:00 EDT 1987 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.36.3971· OSTI ID:6254721

Gao, Y; Wagener, T J; Weaver, J H; Arko, A J; Flandermeyer, B; Capone, II, D W

The energy distribution of the unoccupied electronic states of the high-T/sub c/ superconductor La/sub 1.85/Sr/sub 0.15/CuO/sub 4/ have been identified at room temperature using inverse photoemission. The density of states is very low from E/sub F/ to --3.5 eV above E/sub F/, strong emission features appear 5.8 and 8.7 eV above the Fermi level, E/sub F/, and the empty-state spectrum is unstructured thereafter until at least 25 eV. The prominent empty-state features are confined to an energy interval of --8 eV and are associated with the La 5d and 4f levels. The ratio of 4f intensity to 5d intensity showed a --5 fold increase for incident electron energies of --1500 eV compared to --30 eV. Our empty-state studies showed that the effects of high-energy electron-stimulated desorption were most pronounced --1.6 eV above E/sub F/, and the exposure of the sample to oxygen showed enhancement of these states.

• Research Organization: Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455
• OSTI ID: 6254721
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 36:7; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
656100 -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALINE EARTH METAL COMPOUNDS
CHALCOGENIDES
COLLISIONS
COPPER COMPOUNDS
COPPER OXIDES
CRYSTALS
ELECTRON COLLISIONS
ELECTRONIC STRUCTURE
EMISSION
ENERGY RANGE
ENERGY-LEVEL DENSITY
EV RANGE
EV RANGE 10-100
EV RANGE 100-1000
KEV RANGE
KEV RANGE 01-10
LANTHANUM COMPOUNDS
LANTHANUM OXIDES
MEDIUM TEMPERATURE
OXIDES
OXYGEN COMPOUNDS
PHOTON EMISSION
POLYCRYSTALS
RARE EARTH COMPOUNDS
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
TRANSITION ELEMENT COMPOUNDS