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Title: Observation by resonant angle-resolved photoemission of a critical thickness for 2-dimensional electron gas formation in SrTiO{sub 3} embedded in GdTiO{sub 3}

For certain conditions of layer thickness, the interface between GdTiO{sub 3} (GTO) and SrTiO{sub 3} (STO) in multilayer samples has been found to form a two-dimensional electron gas (2DEG) with very interesting properties including high mobilities and ferromagnetism. We have here studied two trilayer samples of the form [2 nm GTO/1.0 or 1.5 unit cells STO/10 nm GTO] as grown on (001) (LaAlO{sub 3}){sub 0.3}(Sr{sub 2}AlTaO{sub 6}){sub 0.7}, with the STO layer thicknesses being at what has been suggested is the critical thickness for 2DEG formation. We have studied these with Ti-resonant angle-resolved and angle-integrated photoemission and find that the spectral feature in the spectra associated with the 2DEG is present in the 1.5 unit cell sample, but not in the 1.0 unit cell sample. We also observe through core-level spectra additional states in Ti and Sr, with the strength of a low-binding-energy state for Sr being associated with the appearance of the 2DEG, and we suggest it to have an origin in final-state core-hole screening.
Authors:
 [1] ;  [2] ;  [3] ; ; ; ;  [1] ;  [2] ; ; ; ;  [4] ; ; ; ; ; ; ;  [5] ;  [6] more »;  [7] « less
  1. Department of Physics, University of California, 1 Shields Ave, Davis, California 95616 (United States)
  2. (United States)
  3. (Germany)
  4. Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, 91192 Gif sur Yvette Cedex (France)
  5. Materials Department, University of California, Santa Barbara, California 93106-5050 (United States)
  6. Department of Physics, University of California, Santa Barbara, California 93106-9530 (United States)
  7. Peter-Grünberg-Institut PGI-6, Forschungszentrum Jülich, 52425 Jülich (Germany)
Publication Date:
OSTI Identifier:
22486179
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 107; Journal Issue: 23; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; BINDING ENERGY; ELECTRON GAS; LAYERS; PHOTOEMISSION; STRONTIUM TITANATES; THICKNESS; TWO-DIMENSIONAL SYSTEMS