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Title: Tunability of conduction at the LaAlO{sub 3}/SrTiO{sub 3} heterointerface: Thickness and compositional studies

The role of chemistry, film thickness, and oxygen pressure in influencing the electrical and thermal transport properties of LaAlO{sub 3}/SrTiO{sub 3} heterointerfaces is explored. Unit-cell precise growth was accomplished for films between 3 and 160 unit cells thick using reflection high-energy electron diffraction-assisted pulsed-laser deposition. Subsequent temperature-dependent studies of electrical resistivity reveal three important observations: (1) by tuning the laser fluence, we can systematically tune the interfacial conductance in a step-wise manner in this system, (2) all films exhibit a critical thickness of 3–4 unit cells for the onset of conduction, and (3) the nature of the conductance is highly influenced by the stoichiometry of the LaAlO{sub 3} film with La-deficient samples showing dramatic changes with thickness, while stoichiometric and La-excess films show little dependence. Time-domain thermoreflectance studies show a diminished interfacial thermal conductance for the La-deficient films when compared to La-excess and stoichiometric films, suggesting that the interfacial conductance is more influenced by extrinsic factors such as oxygen deficiency.
Authors:
 [1] ;  [2] ;  [3] ;  [2] ;  [3] ;  [4] ;  [2]
  1. Department of Materials Science and Engineering and Materials Research Laboratory, University of Illinois, Urbana-Champaign, Urbana, Illinois 81801 (United States)
  2. (United States)
  3. Department of Physics and Materials Research Laboratory, University of Illinois, Urbana-Champaign, Urbana, Illinois 61801 (United States)
  4. Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, California 94720 (United States)
Publication Date:
OSTI Identifier:
22350746
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 12; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ALUMINATES; CRYSTAL GROWTH; ELECTRIC CONDUCTIVITY; ELECTRON DIFFRACTION; ENERGY BEAM DEPOSITION; FILMS; LANTHANUM COMPOUNDS; LASER RADIATION; PULSED IRRADIATION; REFLECTION; STOICHIOMETRY; STRONTIUM TITANATES; TEMPERATURE DEPENDENCE; THERMAL CONDUCTIVITY; THICKNESS