TY  - JOUR
AU  - Gunkel, F.
AU  - Hoffmann-Eifert, S.
AU  - Heinen, R. A.
AU  - Christensen, D. V.
AU  - Chen, Y. Z.
AU  - Pryds, N.
AU  - Waser, R.
AU  - Dittmann, R.
TI  - Thermodynamic Ground States of Complex Oxide Heterointerfaces
JO  - ACS applied materials & interfaces
VL  - 9
IS  - 1
SN  - 1944-8252
CY  - Washington, DC
PB  - Soc.
M1  - FZJ-2017-00566
SP  - 1086 - 1092
PY  - 2017
AB  - The formation mechanism of 2-dimensional electron gases (2DEGs) at heterointerfaces between nominally insulating oxides is addressed with a thermodynamical approach. We provide a comprehensive analysis of the thermodynamic ground states of various 2DEG systems directly probed in high temperature equilibrium conductivity measurements. We unambiguously identify two distinct classes of oxide heterostructures: For epitaxial perovskite/perovskite heterointerfaces (LaAlO3/SrTiO3, NdGaO3/SrTiO3, and (La,Sr)(Al,Ta)O3/SrTiO3), we find the 2DEG formation being based on charge transfer into the interface, stabilized by the electric field in the space charge region. In contrast, for amorphous LaAlO3/SrTiO3 and epitaxial γ-Al2O3/SrTiO3 heterostructures, the 2DEG formation mainly relies on the formation and accumulation of oxygen vacancies. This class of 2DEG structures exhibits an unstable interface reconstruction associated with a quenched nonequilibrium state.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000392037400124
DO  - DOI:10.1021/acsami.6b12706
UR  - https://juser.fz-juelich.de/record/826338
ER  -