| Autor: |
Lutz, Peter, Moser, Simon, Jovic, Vedran, Chang, Young Jun, Koch, Roland J., Ulstrup, Soren, Oh, Ji Seop, Moreschini, Luca, Fatale, Sara, Grioni, Marco, Jozwiak, Chris, Bostwick, Aaron, Rotenberg, Eli, Bentmann, Hendrik, Reinert, Friedrich |
| Předmět: |
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| Popis: |
We investigate the metallic surface state in ultrathin films of BaTiO3 by angle-resolved photoemission spectroscopy. We find Fermi-surface contours derived from the Ti 3d t(2g) conduction band, similar as in SrTiO3 but with broader spectral features due to enhanced quasiparticle scattering. Oxygen vacancies created in the x-ray beam spot allow for reversible in situ doping control up to surface carrier densities as high as 1014 cm(-2), but vacancy migration into the subsurface at T >= 285 K quenches the surface state. Our analysis suggests that the charge state of oxygen vacancies in ultrathin films is predominantly 2+, which limits charge-carrier trapping and the formation of localized defect states. |
| Databáze: |
OpenAIRE |
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