Facet Stability in Oxygen-Induced Nanofaceting of Re(1231)
Abstract
The stability of the various facets in oxygen-induced faceting of Re(121) has been studied by low-energy electron diffraction, scanning tunneling microcopy, and synchrotron-based high-resolution X-ray photoemission spectroscopy. When Re(121) is annealed at 800-1200 K in oxygen (10-7 Torr), the surface becomes completely covered with nanometer-scale facets, and its morphology depends on the substrate temperature and oxygen exposure. Especially, the (111) facet competes with the (101) facet in determining the surface morphology, and the stability of each facet relies on oxygen coverage. Using density functional theory, the O-Re binding energies on the facets for various oxygen concentrations are calculated to explain how the oxygen coverage affects the anisotropy of surface free energy, which in turn determines the morphology of the faceted surface.
- Authors:
- Publication Date:
- Research Org.:
- Brookhaven National Laboratory (BNL) National Synchrotron Light Source
- Sponsoring Org.:
- Doe - Office Of Science
- OSTI Identifier:
- 960143
- Report Number(s):
- BNL-83129-2009-JA
TRN: US201016%%1287
- DOE Contract Number:
- DE-AC02-98CH10886
- Resource Type:
- Journal Article
- Resource Relation:
- Journal Name: ACS Nano; Journal Volume: 1; Journal Issue: 5
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 77 NANOSCIENCE AND NANOTECHNOLOGY; ANISOTROPY; ELECTRON DIFFRACTION; FREE ENERGY; FUNCTIONALS; MORPHOLOGY; OXYGEN; PHOTOEMISSION; SPECTROSCOPY; STABILITY; SUBSTRATES; TUNNELING; national synchrotron light source
Citation Formats
Wang,H., Chan, A., Chen, W., Kaghazchi, P., Jacob, T., and Madey, T.. Facet Stability in Oxygen-Induced Nanofaceting of Re(1231). United States: N. p., 2007.
Web. doi:10.1021/nn700238r.
Wang,H., Chan, A., Chen, W., Kaghazchi, P., Jacob, T., & Madey, T.. Facet Stability in Oxygen-Induced Nanofaceting of Re(1231). United States. doi:10.1021/nn700238r.
Wang,H., Chan, A., Chen, W., Kaghazchi, P., Jacob, T., and Madey, T.. Mon .
"Facet Stability in Oxygen-Induced Nanofaceting of Re(1231)". United States.
doi:10.1021/nn700238r.
@article{osti_960143,
title = {Facet Stability in Oxygen-Induced Nanofaceting of Re(1231)},
author = {Wang,H. and Chan, A. and Chen, W. and Kaghazchi, P. and Jacob, T. and Madey, T.},
abstractNote = {The stability of the various facets in oxygen-induced faceting of Re(121) has been studied by low-energy electron diffraction, scanning tunneling microcopy, and synchrotron-based high-resolution X-ray photoemission spectroscopy. When Re(121) is annealed at 800-1200 K in oxygen (10-7 Torr), the surface becomes completely covered with nanometer-scale facets, and its morphology depends on the substrate temperature and oxygen exposure. Especially, the (111) facet competes with the (101) facet in determining the surface morphology, and the stability of each facet relies on oxygen coverage. Using density functional theory, the O-Re binding energies on the facets for various oxygen concentrations are calculated to explain how the oxygen coverage affects the anisotropy of surface free energy, which in turn determines the morphology of the faceted surface.},
doi = {10.1021/nn700238r},
journal = {ACS Nano},
number = 5,
volume = 1,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
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We have studied oxygen-induced faceting of the atomically rough Re(1231) surface by means of Auger electron spectroscopy, low energy electron diffraction, and scanning tunneling microscopy (STM). In contrast to previous faceting studies on other refractory metal surfaces, where simple morphologies of the facets were reported, we find a coverage-dependent morphological evolution of the facets ranging from long sawtooth ridges to complex structures exposing four different facets. The faceting occurs only when oxygen coverage ({theta}) exceeds 0.5 monolayer (ML) and the surface is annealed at {>=}700 K. At low oxygen coverage (0.5 ML{<=}{theta}<0.7 ML), the O/Re(1231) surface becomes partially faceted uponmore »
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Evolution of the superconductivity during the pressure-induced oxygen ordering process in oxygen-deficient REBa{sub 2}Cu{sub 3}O{sub 6+x} (RE = Y,Nd,La)
The pressure controlled oxygen reordering processes in REBa{sub 2}Cu{sub 3}O{sub 6+x}(RE = Y,Nd,La) causing the continuous charge transfer between the CuO{sub x} and CuO{sub 2} planes were investigated. The charge transfer results in the time evolution of superconductivity. A strong acceleration of ordering and disordering processes was found when the RE-ion size increases from Y to La. Pressure induced semiconductor-superconductor transition in LaBa{sub 2}Cu{sub 3}O{sub 6+x} resulted from the oxygen ordering is reported for the first time.