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Probing and modifying the empty-state threshold of anatase TiO2: Experiments and ab initio theory

Sandell, A.; Sanyal, B.; Walle, L. E.; Richter, J. H.; Plogmaker, S.; Karlsson, P. G.; Borg, A. and Uvdal, Per LU (2008) In Physical Review B (Condensed Matter and Materials Physics) 78(7).
Abstract
O 1s x-ray absorption spectroscopy (XAS) in conjunction with photoelectron spectroscopy has been used to explore the conduction-band edge of single crystalline and nanostructured anatase TiO2. The experiments are supported by ab initio density-functional calculations in which both the initial and core hole final states are considered. The calculations show that the states at the conduction-band edge of anatase are of pure d(xy) character. This is also the case in the presence of an O 1s core hole. In the O 1s XAS process pure Ti d states cannot be probed and, by appropriate energy referencing, the separation between the Ti d derived conduction-band edge and the threshold of the unoccupied Ti d-O p states can therefore be revealed. The... (More)
O 1s x-ray absorption spectroscopy (XAS) in conjunction with photoelectron spectroscopy has been used to explore the conduction-band edge of single crystalline and nanostructured anatase TiO2. The experiments are supported by ab initio density-functional calculations in which both the initial and core hole final states are considered. The calculations show that the states at the conduction-band edge of anatase are of pure d(xy) character. This is also the case in the presence of an O 1s core hole. In the O 1s XAS process pure Ti d states cannot be probed and, by appropriate energy referencing, the separation between the Ti d derived conduction-band edge and the threshold of the unoccupied Ti d-O p states can therefore be revealed. The electronic charge needed per Ti to eliminate this offset is discussed in quantitative terms. The theoretical and experimental values are in good agreement, showing that 4 +/- 2% of an electronic charge per Ti ion is sufficient to change the character of the empty states at threshold from pure Ti d to Ti d-O p. (Less)
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author
organization
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type
Contribution to journal
publication status
published
subject
in
Physical Review B (Condensed Matter and Materials Physics)
volume
78
issue
7
publisher
American Physical Society
external identifiers
  • wos:000259406700035
  • scopus:50049084123
ISSN
1098-0121
DOI
10.1103/PhysRevB.78.075113
language
English
LU publication?
yes
id
1dfb5f1d-c085-438c-9a1b-257a900dbce8 (old id 1287207)
date added to LUP
2009-01-28 09:17:40
date last changed
2017-08-27 04:56:41
@article{1dfb5f1d-c085-438c-9a1b-257a900dbce8,
  abstract     = {O 1s x-ray absorption spectroscopy (XAS) in conjunction with photoelectron spectroscopy has been used to explore the conduction-band edge of single crystalline and nanostructured anatase TiO2. The experiments are supported by ab initio density-functional calculations in which both the initial and core hole final states are considered. The calculations show that the states at the conduction-band edge of anatase are of pure d(xy) character. This is also the case in the presence of an O 1s core hole. In the O 1s XAS process pure Ti d states cannot be probed and, by appropriate energy referencing, the separation between the Ti d derived conduction-band edge and the threshold of the unoccupied Ti d-O p states can therefore be revealed. The electronic charge needed per Ti to eliminate this offset is discussed in quantitative terms. The theoretical and experimental values are in good agreement, showing that 4 +/- 2% of an electronic charge per Ti ion is sufficient to change the character of the empty states at threshold from pure Ti d to Ti d-O p.},
  author       = {Sandell, A. and Sanyal, B. and Walle, L. E. and Richter, J. H. and Plogmaker, S. and Karlsson, P. G. and Borg, A. and Uvdal, Per},
  issn         = {1098-0121},
  language     = {eng},
  number       = {7},
  publisher    = {American Physical Society},
  series       = {Physical Review B (Condensed Matter and Materials Physics)},
  title        = {Probing and modifying the empty-state threshold of anatase TiO2: Experiments and ab initio theory},
  url          = {http://dx.doi.org/10.1103/PhysRevB.78.075113},
  volume       = {78},
  year         = {2008},
}