Mapping the spatial distribution of charge carriers in LaAlO3/SrTiO3 heterostructures.
At the interface between complex insulating oxides, novel phases with interesting properties may occur, such as the metallic state reported in the LaAlO(3)/SrTiO(3) system . Although this state has been predicted and reported to be confined at the interface, some studies indicate a much broader spatial extension, thereby questioning its origin. Here, we provide for the first time a direct determination of the carrier density profile of this system through resistance profile mappings collected in cross-section LaAlO(3)/SrTiO(3) samples with a conducting-tip atomic force microscope (CT-AFM). We find that, depending on specific growth protocols, the spatial extension of the high-mobility electron gas can be varied from hundreds of micrometres into SrTiO(3) to a few nanometres next to the LaAlO(3)/SrTiO(3) interface. Our results emphasize the potential of CT-AFM as a novel tool to characterize complex oxide interfaces and provide us with a definitive and conclusive way to reconcile the body of experimental data in this system.
Basletic
M
M
Unité Mixte de Physique CNRS/Thales, Associée à l'Université Paris-Sud, Route départementale 128, 91767 Palaiseau Cedex, France.
Maurice
J-L
JL
Carrétéro
C
C
Herranz
G
G
Copie
O
O
Bibes
M
M
Jacquet
E
E
Bouzehouane
K
K
Fusil
S
S
Barthélémy
A
A