1. Observation of a two-dimensional electron gas at the surface of annealed SrTiO3 single crystals by scanning tunneling spectroscopy
- Author
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DI CAPUA, ROBERTO, SCOTTI DI UCCIO, UMBERTO, VAGLIO, RUGGERO, M. Radovic, DE LUCA, GABRIELLA MARIA, I. Maggio Aprile, F. Miletto Granozio, N. C. Plumb, Z. Ristic, M. Salluzzo, DI CAPUA, Roberto, M., Radovic, DE LUCA, GABRIELLA MARIA, I., Maggio Aprile, F., Miletto Granozio, N. C., Plumb, Z., Ristic, SCOTTI DI UCCIO, Umberto, Vaglio, Ruggero, and M., Salluzzo
- Subjects
Condensed Matter - Other Condensed Matter ,Condensed Matter - Materials Science ,Condensed Matter::Materials Science ,Condensed Matter::Superconductivity ,STO, two dimensional electron gas, scanning tunneling spectroscopy, annealing, surface reconstruction ,Materials Science (cond-mat.mtrl-sci) ,FOS: Physical sciences ,Other Condensed Matter (cond-mat.other) - Abstract
Scanning tunneling spectroscopy suggests the formation of a two dimensional electron gas (2DEG) on the TiO2 terminated surface of undoped SrTiO3 single crystals annealed at temperature lower than 400 {\deg}C in ultra high vacuum conditions. Low energy electron diffraction indicates that the 2D metallic SrTiO3 surface is not structurally reconstructed, suggesting that non-ordered oxygen vacancies created in the annealing process introduce carriers leading to an electronic reconstruction. The experimental results are interpreted in a frame of competition between oxygen diffusion from the bulk to the surface and oxygen loss from the surface itself., Comment: 9 pages, 3 figures, submitted to Physical Review B