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Title: X-Ray Standing Wave Analysis of Overlayer-Induced Substrate Relaxation: the Clean And Bi-Covered (110) GaP Surface

Abstract

The relaxation of the surface P atoms, for both the clean and Bi-covered GaP(110) surface, was studied with x-ray standing wave (XSW) spectroscopy using surface-sensitive x-ray photoelectron as the XSW modulated signal. The photoemission signal of the outermost surface layer is mixed with the signal from the remaining near surface of the underlying substrate, so further analysis is required to calculate the geometry of the relaxation of the surface atoms. We present a general analysis method for extracting the geometry of the surface reconstruction that minimizes the propagation of the uncertainties associated with fitting XSW data. It takes advantage of the fact that the coherent distance may be more accurately determined than the coherent fraction in XSW data analysis. This method makes use of the electron attenuation length, and shows that the relaxation is only weakly dependent on the uncertainties of this parameter. Results indicate that, for the clean GaP surface, P relaxes with a small outward rotational displacement, with the axis of the rotation located at the second-layer Ga site, whereas, for the Bi-covered case, relaxation consists of a rotation in the opposite direction. The magnitude of the contraction is not negligible, and might be important in the interpretationmore » of low-energy electron diffraction data and in ab initio calculations.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
953992
Report Number(s):
SLAC-REPRINT-2009-400
Journal ID: ISSN 1098-0121; TRN: US201004%%729
DOE Contract Number:  
AC02-76SF00515
Resource Type:
Journal Article
Journal Name:
Phys. Rev. B75:165318,2007
Additional Journal Information:
Journal Volume: 75; Journal Issue: 16; Journal ID: ISSN 1098-0121
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ATOMS; ATTENUATION; CONTRACTION; DATA ANALYSIS; DISTANCE; ELECTRON DIFFRACTION; ELECTRONS; LAYERS; LENGTH; PHOTOEMISSION; RELAXATION; ROTATION; SIGNALS; SPECTROSCOPY; STANDING WAVES; SUBSTRATES; SURFACES; Other,OTHER, PHYS

Citation Formats

Herrera-Gomez, A, Woicik, J C, Kendelewicz, T, Miyano, K E, and Spicer, W E. X-Ray Standing Wave Analysis of Overlayer-Induced Substrate Relaxation: the Clean And Bi-Covered (110) GaP Surface. United States: N. p., 2009. Web.
Herrera-Gomez, A, Woicik, J C, Kendelewicz, T, Miyano, K E, & Spicer, W E. X-Ray Standing Wave Analysis of Overlayer-Induced Substrate Relaxation: the Clean And Bi-Covered (110) GaP Surface. United States.
Herrera-Gomez, A, Woicik, J C, Kendelewicz, T, Miyano, K E, and Spicer, W E. 2009. "X-Ray Standing Wave Analysis of Overlayer-Induced Substrate Relaxation: the Clean And Bi-Covered (110) GaP Surface". United States.
@article{osti_953992,
title = {X-Ray Standing Wave Analysis of Overlayer-Induced Substrate Relaxation: the Clean And Bi-Covered (110) GaP Surface},
author = {Herrera-Gomez, A and Woicik, J C and Kendelewicz, T and Miyano, K E and Spicer, W E},
abstractNote = {The relaxation of the surface P atoms, for both the clean and Bi-covered GaP(110) surface, was studied with x-ray standing wave (XSW) spectroscopy using surface-sensitive x-ray photoelectron as the XSW modulated signal. The photoemission signal of the outermost surface layer is mixed with the signal from the remaining near surface of the underlying substrate, so further analysis is required to calculate the geometry of the relaxation of the surface atoms. We present a general analysis method for extracting the geometry of the surface reconstruction that minimizes the propagation of the uncertainties associated with fitting XSW data. It takes advantage of the fact that the coherent distance may be more accurately determined than the coherent fraction in XSW data analysis. This method makes use of the electron attenuation length, and shows that the relaxation is only weakly dependent on the uncertainties of this parameter. Results indicate that, for the clean GaP surface, P relaxes with a small outward rotational displacement, with the axis of the rotation located at the second-layer Ga site, whereas, for the Bi-covered case, relaxation consists of a rotation in the opposite direction. The magnitude of the contraction is not negligible, and might be important in the interpretation of low-energy electron diffraction data and in ab initio calculations.},
doi = {},
url = {https://www.osti.gov/biblio/953992}, journal = {Phys. Rev. B75:165318,2007},
issn = {1098-0121},
number = 16,
volume = 75,
place = {United States},
year = {Mon Jun 01 00:00:00 EDT 2009},
month = {Mon Jun 01 00:00:00 EDT 2009}
}