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Title: SrTiO{sub 3}(001)-({radical}(5)x{radical}(5))-R26.6 deg. reconstruction: A surface resulting from phase separation in a reducing environment

Abstract

Scanning tunneling microscopy (STM) was used to produce atomic resolution images of the Nb-doped SrTiO{sub 3}(001)-({radical}(5)x{radical}(5))-R26.6 deg. reconstruction and its precursor surfaces. Low-energy electron diffraction was used to identify the surface structure in combination with the STM imaging. The ({radical}(5)x{radical}(5))-R26.6 deg. reconstruction was observed growing as an adlayer on top of the underlying terraces. The formation of this structure could routinely be detected by an increase in the crystal's electrical conductivity during ultrahigh vacuum (UHV) annealing at 1300 deg. C. This rise in conductivity occurs due to significant reduction of the crystal. Scanning electron microscopy (SEM) on these samples showed small islands with a rectangular base separated by flat regions. Auger electron spectroscopy showed titanium enrichment, and strontium and oxygen depletion of the surface region. The islands seen in the SEM images are TiO crystals, as reported by S. B. Lee et al. [Ultramicroscopy 104, 30 (2005)]. The flat regions between the islands are composed of a Sr adlayer on the surface that is consistent with the ({radical}(5)x{radical}(5))-R26.6 deg. adatom model of Kubo and Nazoye [Phys. Rev. Lett. 86, 1801 (2001)]. We propose that the TiO islands and the ({radical}(5)x{radical}(5))-R26.6 deg. Sr adlayer reconstruction form due to phase separation inmore » the surface region of the crystal. This phase separation is driven by oxygen depletion which occurs during high-temperature UHV annealing of the sample.« less

Authors:
; ;  [1];  [2]
  1. Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom)
  2. Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ (United Kingdom)
Publication Date:
OSTI Identifier:
21045883
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. B, Condensed Matter and Materials Physics; Journal Volume: 75; Journal Issue: 20; Other Information: DOI: 10.1103/PhysRevB.75.205429; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 36 MATERIALS SCIENCE; ANNEALING; AUGER ELECTRON SPECTROSCOPY; CRYSTALS; DOPED MATERIALS; ELECTRIC CONDUCTIVITY; ELECTRON DIFFRACTION; FERROELECTRIC MATERIALS; LAYERS; NEODYMIUM; OXYGEN; SCANNING ELECTRON MICROSCOPY; SCANNING TUNNELING MICROSCOPY; STRONTIUM; STRONTIUM TITANATES; SURFACES; TEMPERATURE RANGE 0400-1000 K; THIN FILMS; TITANIUM; TITANIUM OXIDES

Citation Formats

Newell, David T., Silly, Fabien, Castell, Martin R., and Harrison, Alastair. SrTiO{sub 3}(001)-({radical}(5)x{radical}(5))-R26.6 deg. reconstruction: A surface resulting from phase separation in a reducing environment. United States: N. p., 2007. Web. doi:10.1103/PHYSREVB.75.205429.
Newell, David T., Silly, Fabien, Castell, Martin R., & Harrison, Alastair. SrTiO{sub 3}(001)-({radical}(5)x{radical}(5))-R26.6 deg. reconstruction: A surface resulting from phase separation in a reducing environment. United States. doi:10.1103/PHYSREVB.75.205429.
Newell, David T., Silly, Fabien, Castell, Martin R., and Harrison, Alastair. Tue . "SrTiO{sub 3}(001)-({radical}(5)x{radical}(5))-R26.6 deg. reconstruction: A surface resulting from phase separation in a reducing environment". United States. doi:10.1103/PHYSREVB.75.205429.
@article{osti_21045883,
title = {SrTiO{sub 3}(001)-({radical}(5)x{radical}(5))-R26.6 deg. reconstruction: A surface resulting from phase separation in a reducing environment},
author = {Newell, David T. and Silly, Fabien and Castell, Martin R. and Harrison, Alastair},
abstractNote = {Scanning tunneling microscopy (STM) was used to produce atomic resolution images of the Nb-doped SrTiO{sub 3}(001)-({radical}(5)x{radical}(5))-R26.6 deg. reconstruction and its precursor surfaces. Low-energy electron diffraction was used to identify the surface structure in combination with the STM imaging. The ({radical}(5)x{radical}(5))-R26.6 deg. reconstruction was observed growing as an adlayer on top of the underlying terraces. The formation of this structure could routinely be detected by an increase in the crystal's electrical conductivity during ultrahigh vacuum (UHV) annealing at 1300 deg. C. This rise in conductivity occurs due to significant reduction of the crystal. Scanning electron microscopy (SEM) on these samples showed small islands with a rectangular base separated by flat regions. Auger electron spectroscopy showed titanium enrichment, and strontium and oxygen depletion of the surface region. The islands seen in the SEM images are TiO crystals, as reported by S. B. Lee et al. [Ultramicroscopy 104, 30 (2005)]. The flat regions between the islands are composed of a Sr adlayer on the surface that is consistent with the ({radical}(5)x{radical}(5))-R26.6 deg. adatom model of Kubo and Nazoye [Phys. Rev. Lett. 86, 1801 (2001)]. We propose that the TiO islands and the ({radical}(5)x{radical}(5))-R26.6 deg. Sr adlayer reconstruction form due to phase separation in the surface region of the crystal. This phase separation is driven by oxygen depletion which occurs during high-temperature UHV annealing of the sample.},
doi = {10.1103/PHYSREVB.75.205429},
journal = {Physical Review. B, Condensed Matter and Materials Physics},
number = 20,
volume = 75,
place = {United States},
year = {Tue May 15 00:00:00 EDT 2007},
month = {Tue May 15 00:00:00 EDT 2007}
}