Microscopic origin of the mobility enhancement at a spinel/perovskite oxide heterointerface revealed by photoemission spectroscopy

P. Schuetz, Dennis Valbjørn Christensen, V. Borisov, F. Pfaff, P. Scheiderer, L. Dudy, M. Zapf, J. Gabel, Y. Z. Chen, Nini Pryds, V. A. Rogalev, V. N. Strocov, C. Schlueter, T. -L. Lee, H. O. Jeschke, R. Valenti, M. Sing, R. Claessen

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Abstract

The spinel/perovskite heterointerface γ−Al2O3/SrTiO3 hosts a two-dimensional electron system (2DES) with electron mobilities exceeding those in its all-perovskite counterpart LaAlO3/SrTiO3 by more than an order of magnitude, despite the abundance of oxygen vacancies which act as electron donors as well as scattering sites. By means of resonant soft x-ray photoemission spectroscopy and ab initio calculations, we reveal the presence of a sharply localized type of oxygen vacancies at the very interface due to the local breaking of the perovskite symmetry. We explain the extraordinarily high mobilities by reduced scattering resulting from the preferential formation of interfacial oxygen vacancies and spatial separation of the resulting 2DES in deeper SrTiO3 layers. Our findings comply with transport studies and pave the way towards defect engineering at interfaces of oxides with different crystal structures.
Original languageEnglish
Article number161409
JournalPhysical Review B
Volume96
Issue number16
Number of pages6
ISSN2469-9950
DOIs
Publication statusPublished - 2017

Bibliographical note

©2017 American Physical Society

Cite this

Schuetz, P., Christensen, D. V., Borisov, V., Pfaff, F., Scheiderer, P., Dudy, L., Zapf, M., Gabel, J., Chen, Y. Z., Pryds, N., Rogalev, V. A., Strocov, V. N., Schlueter, C., Lee, T. -L., Jeschke, H. O., Valenti, R., Sing, M., & Claessen, R. (2017). Microscopic origin of the mobility enhancement at a spinel/perovskite oxide heterointerface revealed by photoemission spectroscopy. Physical Review B, 96(16), [161409]. https://doi.org/10.1103/PhysRevB.96.161409