Overview of two-dimensional electron gases based on the LaAlO3/SrTiO3 interface- Dr Thomas Fix -Device Materials Group

T. Fix, F. Schoofs, J. L. MacManus-Driscoll and M. G. Blamire.
Department of Materials Science, University of Cambridge, Cambridge, United Kingdom
The origin of the free charge layer which forms at the LaAlO3/SrTiO3 interface [1] is still uncertain. Still the impact of defects on the conduction properties can provide useful information to understand this system. The defects that we will consider here can be induced by the substrate steps, by the deposition parameters, or can be voluntarily introduced in the form of dopants. By varying the dopant distance from the interface, the doping concentration and the nature of the dopant in SrTiO3 at the LaAlO3/SrTiO3 interface we show the extreme sensitivity of the system and confirm that the underlying phenomenon accounting for the conduction is most likely an electronic reconstruction, with the majority of the carriers confined within 1 unit cell of the interface [2,3]. This talk will give an overview of all the work on LaAlO3/SrTiO3 in our group.
[1] Ohtomo A., Hwang, H. Y., Nature 427, 423 (2004).
[2] T. Fix, J.L. MacManus-Driscoll, M.G. Blamire, Appl. Phys. Lett. 94, 172101 (2009).
[3] T. Fix, F. Schoofs, J.L. MacManus-Driscoll, and M.G. Blamire, Phys. Rev. Lett. 103, 166802 (2009).