Kelvin Probe Force Microscopy Study of LaAlO3/SrTiO3 Heterointerfaces

Vladimir Popok, Alexey Kalabukhov, Robert Gunnarsson, Sergey Lemeshko, Tord Claeson, Dag Winkler

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9 Citationer (Scopus)


Surface potential distributions in ultra-thin (0.8-3.9 nm) LaAlO3 layers deposited on SrTiO3 substrates are studied by Kelvin probe force microscopy. 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 below 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.
TidsskriftJournal of Advanced Microscopy Research
Udgave nummer1
Sider (fra-til)26-30
Antal sider5
StatusUdgivet - apr. 2010
Udgivet eksterntJa


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