We 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.
Transition from a uni- to a bimodal interfacial charge distribution in LaAlO 3 / SrTiO 3 upon cooling / Zwiebler, M.; Di Gennaro, E.; Hamann-Borrero, J. E.; Ritschel, T.; Green, R. J.; Sawatzky, G. A.; Schierle, E.; Weschke, E.; Leo, A.; Granozio, F. M.; Geck, J.. - In: SCIENTIFIC REPORTS. - ISSN 2045-2322. - 10:1(2020), p. 18359. [10.1038/s41598-020-74364-7]
Transition from a uni- to a bimodal interfacial charge distribution in LaAlO 3 / SrTiO 3 upon cooling
Di Gennaro E.;Leo A.;
2020
Abstract
We 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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
