The origin of electronic states at the basis of the 2DEG found in conducting LaAlO 3 /SrTiO 3 interfaces (5 u.c. LaAlO 3 ) is investigated by resonant photoemission experiments at the Ti L 2,3 and La M 4,5 edges. As shown by the resonant enhancement at the Ti L 2,3 edge, electronic states at E F receive a dominant contribution from Ti 3d states. Both Ti and La resonance effects in the valence-band region are used to estimate the valence-band maxima at the two sides of the junction. Through a comparison with the valence-band states of the LaAlO 3 and SrTiO 3 parent compounds, we reconstruct the band diagram of the heterojunction, which is revealed to be type I (straddling gap), with a large notch of the band profile at the interface as compared with the reference insulating (3 u.c. LaAlO 3 ) interface.
|Journal||Physical Review B (Condensed Matter and Materials Physics)|
|Publication status||Published - 2014|
Drera, G., Salvinelli, G., Bondino, F., Magnano, E., Huijben, M., Brinkman, A., & Sangaletti, L. (2014). Intrinsic origin of interface states and band offset profiling of nanostructured LaAlO3/SrTiO3 heterojunctions probed by element-specific resonant spectroscopies. Physical Review B (Condensed Matter and Materials Physics), 90(3), -. . https://doi.org/10.1103/PhysRevB.90.035124