Origin of charge density at LaAlO3 on SrTiO3 heterointerfaces: possibility of intrinsic doping

W. Siemons, Gertjan Koster, Hideki Yamamoto, Walter A. Harrison, Gerald Lucovsky, Theodore H. Geballe, David H.A. Blank, Malcolm R. Beasley

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Abstract

As discovered by Ohtomo and Hwang, a large sheet charge density with high mobility exists at the interface between SrTiO3 and LaAlO3. Based on transport, spectroscopic, and oxygen-annealing experiments, we conclude that extrinsic defects in the form of oxygen vacancies introduced by the pulsed laser deposition process used by all researchers to date to make these samples is the source of the large carrier densities. Annealing experiments show a limiting carrier density. We also present a model that explains the high mobility based on carrier redistribution due to an increased dielectric constant.
Original languageUndefined
Pages (from-to)196802-
Number of pages4
JournalPhysical review letters
Volume98
Issue number19
DOIs
Publication statusPublished - 2007

Keywords

  • IR-59119
  • METIS-242616

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