Identifying Ionic and Electronic Charge Transfer at Oxide Heterointerfaces

Advanced Materials, vol. 33, pp. e2004132

Abstract

Abstract The ability to tailor oxide heterointerfaces has led to novel properties in low‐dimensional oxide systems. A fundamental understanding of these properties is based on the concept of electronic charge transfer. However, the electronic properties of oxide heterointerfaces crucially depend on their ionic constitution and defect structure: ionic charges contribute to charge transfer and screening at oxide interfaces, triggering a thermodynamic balance of ionic and electronic structures. Quantitative understanding of the electronic and ionic roles regarding charge‐transfer phenomena poses a central challenge. Here, the electronic and ionic structure is simultaneously investigated at the prototypical charge‐transfer heterointerface, LaAlO3/SrTiO3. Applying in situ photoemission spectroscopy under oxygen ambient, ionic and electronic charge transfer is deconvoluted in response to the oxygen atmosphere at elevated temperatures. In this way, both the rich and variable chemistry of complex oxides and the associated electronic properties are equally embraced. The interfacial electron gas is depleted through an ionic rearrangement in the strontium cation sublattice when oxygen is applied, resulting in an inverse and reversible balance between cation vacancies and electrons, while the mobility of ionic species is found to be considerably enhanced as compared to the bulk. Triggered by these ionic phenomena, the electronic transport and magnetic signature of the heterointerface are significantly altered.

Authors 12

1. Marc‐André Rose corresponding Aachen Institute for Electronic Materials (IWE 2)

   Forschungszentrum Jülich · Jülich Aachen Research Alliance · RWTH Aachen University

   Affiliation as printed

   Institute for Electronic Materials (IWE 2), and Juelich‐Aachen Research Alliance for Fundamentals on Future Information Technology (JARA‐FIT) RWTH Aachen University 52074 Aachen Germany

   Peter Grünberg Institute 7 Forschungszentrum Jülich GmbH, and JARA‐FIT 52425 Jülich Germany

   Institute for Electronic Materials (IWE 2), and Juelich-Aachen Research Alliance for Fundamentals on Future Information Technology (JARA-FIT), RWTH Aachen University, 52074 Aachen, Germany

2. Břetislav Šmíd

   Charles University

   Affiliation as printed

   Department of Surface and Plasma Science Faculty of Mathematics and Physics Charles University Prague 180 00 Czech Republic

   Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, Prague, 180 00 Czech Republic

3. Mykhailo Vorokhta

   Charles University

   Affiliation as printed

   Department of Surface and Plasma Science Faculty of Mathematics and Physics Charles University Prague 180 00 Czech Republic

   Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, Prague, 180 00 Czech Republic

4. Ivetta Slipukhina

   Forschungszentrum Jülich · Jülich Aachen Research Alliance

   Affiliation as printed

   Peter Grünberg Institute 1 and Institute for Advanced Simulation Forschungszentrum Jülich GmbH and JARA‐FIT 52425 Jülich Germany

5. Michael Andrä

   Forschungszentrum Jülich · Jülich Aachen Research Alliance

   Affiliation as printed

   Peter Grünberg Institute 7 Forschungszentrum Jülich GmbH, and JARA‐FIT 52425 Jülich Germany

6. Hendrik Bluhm

   Lawrence Berkeley National Laboratory · Fritz Haber Institute of the Max Planck Society

   Affiliation as printed

   Chemical Sciences Division Lawrence Berkeley National Lab. Berkeley CA 94720 USA

   Department of Inorganic Chemistry Fritz Haber Institute of the Max Planck Society 14195 Berlin Germany

   Chemical Sciences Division, Lawrence Berkeley National Lab., Berkeley, CA, 94720 USA

   Department of Inorganic Chemistry, Fritz Haber Institute of the Max Planck Society, 14195 Berlin, Germany

7. Tomáš Duchoň

   Forschungszentrum Jülich · Jülich Aachen Research Alliance

   Affiliation as printed

   Peter Grünberg Institute 6, and JARA‐FIT Forschungszentrum Jülich GmbH 52425 Jülich Germany

8. Marjana Ležaić

   Forschungszentrum Jülich · Jülich Aachen Research Alliance

   Affiliation as printed

   Peter Grünberg Institute 1 and Institute for Advanced Simulation Forschungszentrum Jülich GmbH and JARA‐FIT 52425 Jülich Germany

9. Scott A. Chambers

   Pacific Northwest National Laboratory

   Affiliation as printed

   Physical and Computational Sciences Directorate Pacific Northwest National Laboratory Richland WA 99354 USA

   Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99354 USA

10. Regina Dittmann

    Forschungszentrum Jülich · Jülich Aachen Research Alliance

    Affiliation as printed

    Peter Grünberg Institute 7 Forschungszentrum Jülich GmbH, and JARA‐FIT 52425 Jülich Germany

11. David N. Mueller corresponding

    Forschungszentrum Jülich · Jülich Aachen Research Alliance

    Affiliation as printed

    Peter Grünberg Institute 6, and JARA‐FIT Forschungszentrum Jülich GmbH 52425 Jülich Germany

    Peter Grünberg Institute 7 Forschungszentrum Jülich GmbH, and JARA‐FIT 52425 Jülich Germany

12. Felix Gunkel corresponding Aachen Institute for Electronic Materials (IWE 2)

    Forschungszentrum Jülich · Jülich Aachen Research Alliance · RWTH Aachen University

    Affiliation as printed

    Institute for Electronic Materials (IWE 2), and Juelich‐Aachen Research Alliance for Fundamentals on Future Information Technology (JARA‐FIT) RWTH Aachen University 52074 Aachen Germany

    Peter Grünberg Institute 7 Forschungszentrum Jülich GmbH, and JARA‐FIT 52425 Jülich Germany

    Institute for Electronic Materials (IWE 2), and Juelich-Aachen Research Alliance for Fundamentals on Future Information Technology (JARA-FIT), RWTH Aachen University, 52074 Aachen, Germany