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Identifying Ionic and Electronic Charge Transfer at Oxide Heterointerfaces
Author(s) -
Rose MarcAndré,
Šmíd Břetislav,
Vorokhta Mykhailo,
Slipukhina Ivetta,
Andrä Michael,
Bluhm Hendrik,
Duchoň Tomáš,
Ležaić Marjana,
Chambers Scott A.,
Dittmann Regina,
Mueller David N.,
Gunkel Felix
Publication year - 2021
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.202004132
Subject(s) - ionic bonding , ionic potential , chemical physics , materials science , oxide , electronic structure , x ray photoelectron spectroscopy , ion , chemistry , computational chemistry , nuclear magnetic resonance , physics , metallurgy , organic chemistry
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, LaAlO 3 /SrTiO 3 . 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.