CC BY 4.0 UnportedZwiebler, M.Di Gennaro, E.Hamann-Borrero, J.E.Ritschel, T.Green, R.J.Sawatzky, G.A.Schierle, E.Weschke, E.Leo, A.Granozio, F. MilettoGeck, J.2022-12-052022-12-052020https://oa.tib.eu/renate/handle/123456789/10497http://dx.doi.org/10.34657/9533We present a combined resonant soft X-ray reflectivity and electric transport study of LaAlO 3/SrTiO 3 field effect devices. The depth profiles with atomic layer resolution that are obtained from the resonant reflectivity reveal a pronounced temperature dependence of the two-dimensional electron liquid at the LaAlO 3/SrTiO 3 interface. At room temperature the corresponding electrons are located close to the interface, extending down to 4 unit cells into the SrTiO 3 substrate. Upon cooling, however, these interface electrons assume a bimodal depth distribution: They spread out deeper into the SrTiO 3 and split into two distinct parts, namely one close to the interface with a thickness of about 4 unit cells and another centered around 9 unit cells from the interface. The results are consistent with theoretical predictions based on oxygen vacancies at the surface of the LaAlO 3 film and support the notion of a complex interplay between structural and electronic degrees of freedom. © 2020, The Author(s).enghttps://creativecommons.org/licenses/by/4.0/500600Article