Electronic structure of LiCoO{sub 2} thin films: A combined photoemission spectroscopy and density functional theory study
- Fachbereich Materialwissenschaften, Fachgebiet Oberflaechenforschung, Technische Universitaet Darmstadt, Petersenstrasse 23, D-64287 Darmstadt (Germany)
- Eduard-Zintl-Institut fuer Anorganische und Physikalische Chemie, Technische Universitaet Darmstadt, Petersenstrasse 21, D-64287 Darmstadt (Germany)
The electronic properties of LiCoO{sub 2} have been studied by theoretical band-structure calculations (using density functional theory) and experimental methods (photoemission). Synchrotron-induced photoelectron spectroscopy, resonant photoemission spectroscopy (ResPES), and soft x-ray absorption (XAS) have been applied to investigate the electronic structure of both occupied and unoccupied states. High-quality PES spectra were obtained from stoichiometric and highly crystalline LiCoO{sub 2} thin films deposited ''in situ'' by rf magnetron sputtering. An experimental approach of separating oxygen- and cobalt-derived (final) states by ResPES in the valence-band region is presented. The procedure takes advantage of an antiresonant behavior of cobalt-derived states at the 3p-3d excitation threshold. Information about the unoccupied density of states has been obtained by O K XAS. The structure of the Co L absorption edge is compared to semiempirical charge-transfer multiplet calculations. The experimental results are furthermore compared with band-structure calculations considering three different exchange potentials [generalized gradient approximation (GGA), using a nonlocal Hubbard U (GGA+U) and using a hybrid functional (Becke, three-parameter, Lee-Yang-Parr [B3LYP])]. For these different approaches total density of states and partial valence-band density of states have been investigated. The best qualitative agreement with experimental results has been obtained by using a GGA+U functional with U=2.9 eV.
- OSTI ID:
- 21502888
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 82, Issue 19; Other Information: DOI: 10.1103/PhysRevB.82.195431; (c) 2010 The American Physical Society; ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ABSORPTION
ABSORPTION SPECTROSCOPY
APPROXIMATIONS
COBALT COMPOUNDS
DENSITY
DENSITY FUNCTIONAL METHOD
ELECTRONIC STRUCTURE
EXCITATION
LITHIUM COMPOUNDS
MAGNETRONS
OXYGEN COMPOUNDS
PHOTOELECTRON SPECTROSCOPY
PHOTOEMISSION
SIMULATION
SOFT X RADIATION
SPECTRA
STOICHIOMETRY
THIN FILMS
X-RAY SPECTROSCOPY
ALKALI METAL COMPOUNDS
CALCULATION METHODS
ELECTROMAGNETIC RADIATION
ELECTRON SPECTROSCOPY
ELECTRON TUBES
ELECTRONIC EQUIPMENT
EMISSION
ENERGY-LEVEL TRANSITIONS
EQUIPMENT
FILMS
IONIZING RADIATIONS
MICROWAVE EQUIPMENT
MICROWAVE TUBES
PHYSICAL PROPERTIES
RADIATIONS
SECONDARY EMISSION
SORPTION
SPECTROSCOPY
TRANSITION ELEMENT COMPOUNDS
VARIATIONAL METHODS
X RADIATION