Kelvin Probe Force Microscopy Study of LaAlO3/SrTiO3 Heterointerfaces
Journal article, 2010
Surface potential distributions in ultra-thin (0.8-3.9 nm) LaAlO3 layers deposited on SrTiO3 substrates are studied. It is found that the potential distribution evolves from island-like to a homogeneous one with increasing LaAlO3 thickness. It is suggested that the observed islands are caused by a locally enhanced concentration of mobile charge carriers at the interface that is, in turn, related to non-stoichiometry of the layers with thickness bellow 4 unit cells. Transition to a homogeneous potential distribution with increasing LAO thickness (≥4 unit cells) corresponds to the formation of a quasi-2-dimensional electron gas. The results agree with a percolation model explaining the insulator-to-metal transition that occurs at the LaAlO3/SrTiO3 heterointerface.
LaAlO 3/SrTiO 3 Heterointerface
Kelvin Probe Force Microscopy
Author
Vladimir Popok
Eindhoven University of Technology
University of Gothenburg
Alexei Kalaboukhov
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics
Robert Gunnarsson
Chalmers, Microtechnology and Nanoscience (MC2), Applied Quantum Physics
S. Lemenshko
Chalmers, Microtechnology and Nanoscience (MC2)
Tord Claeson
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics
Dag Winkler
Chalmers, Microtechnology and Nanoscience (MC2)
Journal of Advanced Microscopy Research
2156-7573 (ISSN) 2156-7581 (eISSN)
Vol. 5 1 26-30Areas of Advance
Nanoscience and Nanotechnology
Materials Science
Subject Categories
Other Engineering and Technologies not elsewhere specified
Condensed Matter Physics
DOI
10.1166/jamr.2010.1020