%0 Journal Article
%A Gunkel, F.
%A Lenser, C.
%A Baeumer, C.
%A Borgatti, F.
%A Offi, F.
%A Panaccione, G.
%A Dittmann, R.
%T Charge-transfer in B-site-depleted NdGaO 3 /SrTiO 3 heterostructures
%J APL materials
%V 6
%N 7
%@ 2166-532X
%C Melville, NY
%I AIP Publ.
%M FZJ-2018-04658
%P 076104 -
%D 2018
%X Cation stoichiometry has been identified as a major key in establishing 2-dimensional electron gases (2DEGs) in oxide heterostructures. Here, we discuss a 2DEG formation scenario in B-site deficient perovskite/perovskite heterostructures, which previously were predicted to show insulating behavior. We elaborate an ionic picture based on oxygen-vacancy-buffered B-site vacancy defects in the polar oxide layer that yields a continuous transition from 2DEG formation to less conducting interfaces to insulating interfaces with increasing B-site deficiency. Experimentally, a corresponding modulation of charge transfer across NdGaO3/SrTiO3 interfaces is inferred using hard x-ray photoelectron spectroscopy analysis and transport experiments. With increasing B-site deficiency, we observe a decrease of the interfacial Ti3+ core level contribution, indicating a reduced charge transfer at the interface. This result is corroborated by temperature-dependent transport measurements, revealing increased low temperature resistance, with a dominant influence of a reduced electron density in the Ga-depleted sample. We consider a redistribution of oxygen vacancies in the B-site deficient polar oxide layer to explain the alleviated interface reconstruction, adding a new perspective on potential built-up in polar-oxide thin films.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000440603600006
%R 10.1063/1.5038773
%U https://juser.fz-juelich.de/record/850927