TY  - JOUR
AU  - Gunkel, F.
AU  - Lenser, C.
AU  - Baeumer, C.
AU  - Borgatti, F.
AU  - Offi, F.
AU  - Panaccione, G.
AU  - Dittmann, R.
TI  - Charge-transfer in B-site-depleted NdGaO 3 /SrTiO 3 heterostructures
JO  - APL materials
VL  - 6
IS  - 7
SN  - 2166-532X
CY  - Melville, NY
PB  - AIP Publ.
M1  - FZJ-2018-04658
SP  - 076104 -
PY  - 2018
AB  - 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.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000440603600006
DO  - DOI:10.1063/1.5038773
UR  - https://juser.fz-juelich.de/record/850927
ER  -