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Title: Two charged states of hydrogen on the SrTiO{sub 3}(001) surface

The effects of hydrogen exposure on the electronic structure of two types of SrTiO{sub 3}(001) surfaces, oxygen-deficient (OD) and nearly-vacancy-free (NVF) surfaces, were investigated with ultraviolet photoemission spectroscopy and nuclear reaction analysis. Upon molecular hydrogen exposure to the OD surface which reveals in-gap states at 1.3 eV below the Fermi level, the in-gap state intensity was reduced to half the initial value at a hydrogen coverage of 0.9 ± 0.7 × 10{sup 14} cm{sup −2}. On the NVF surface which has no in-gap state, on the other hand, atomic-hydrogen exposure induced in-gap states, and the hydrogen saturation coverage was evaluated to be 3.1 ± 0.8 × 10{sup 14} cm{sup −2}. We argue that H is positively charged as H{sup ∼0.3+} on the NVF surface by being coordinated to the O atom, whereas H is negatively charged as H{sup −} on the OD surface by occupying the oxygen vacancy site. The stability of H{sup −} at the oxygen vacancy site is discussed.
Authors:
; ; ; ;  [1]
  1. Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153–8505 (Japan)
Publication Date:
OSTI Identifier:
22255067
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 140; Journal Issue: 8; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ELECTRONIC STRUCTURE; FERMI LEVEL; HYDROGEN; NUCLEAR REACTION ANALYSIS; OXYGEN; PHOTOEMISSION; SPECTROSCOPY; STRONTIUM TITANATES; SURFACES