1202.0634 (R. Di Capua et al.)

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

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

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.

View original: http://arxiv.org/abs/1202.0634