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arXiv · 1202.0634

Observation of a two-dimensional electron gas at the surface of annealed SrTiO3 single crystals by scanning tunneling spectroscopy

R. Di Capua·M. Radovic·G. M. De Luca·I. Maggio-Aprile·F. Miletto Granozio·N. C. Plumb·Z. Ristic·U. Scotti di Uccio·R. Vaglio·M. Salluzzo
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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.

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R. Di Capua, M. Radovic, G. M. De Luca, I. Maggio-Aprile, F. Miletto Granozio, N. C. Plumb, Z. Ristic, U. Scotti di Uccio, R. Vaglio, M. Salluzzo. 2012-02-03. Observation of a two-dimensional electron gas at the surface of annealed SrTiO3 single crystals by scanning tunneling spectroscopy. https://doi.org/10.1103/physrevb.86.155425

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