A reverse Monte Carlo method for deriving optical constants of solids from reflection electron energy-loss spectroscopy spectra

Journal Article · Fri Jun 07 00:00:00 EDT 2013 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4809544· OSTI ID:22162995

Da, B.; Sun, Y.; Ding, Z. J. ^[1]; Mao, S. F. ^[2]; Zhang, Z. M. ^[3]; Jin, H.; Yoshikawa, H.; Tanuma, S. ^[4]

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1. Hefei National Laboratory for Physical Sciences at Microscale and Department of Physics, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, People's Republic of China (China)
2. School of Nuclear Science and Technology, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, People's Republic of China (China)
3. Centre of Physical Experiments, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, People's Republic of China (China)
4. Advanced Surface Chemical Analysis Group, National Institute for Materials Science, 1-2-1 Sengen Tsukuba, Ibaraki 305-0047 (Japan)

A reverse Monte Carlo (RMC) method is developed to obtain the energy loss function (ELF) and optical constants from a measured reflection electron energy-loss spectroscopy (REELS) spectrum by an iterative Monte Carlo (MC) simulation procedure. The method combines the simulated annealing method, i.e., a Markov chain Monte Carlo (MCMC) sampling of oscillator parameters, surface and bulk excitation weighting factors, and band gap energy, with a conventional MC simulation of electron interaction with solids, which acts as a single step of MCMC sampling in this RMC method. To examine the reliability of this method, we have verified that the output data of the dielectric function are essentially independent of the initial values of the trial parameters, which is a basic property of a MCMC method. The optical constants derived for SiO{sub 2} in the energy loss range of 8-90 eV are in good agreement with other available data, and relevant bulk ELFs are checked by oscillator strength-sum and perfect-screening-sum rules. Our results show that the dielectric function can be obtained by the RMC method even with a wide range of initial trial parameters. The RMC method is thus a general and effective method for determining the optical properties of solids from REELS measurements.

• OSTI ID: 22162995
• Journal Information: Journal of Applied Physics, Vol. 113, Issue 21; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANNEALING
DIELECTRIC MATERIALS
ENERGY GAP
ENERGY LOSSES
ENERGY-LOSS SPECTROSCOPY
EXCITATION
ITERATIVE METHODS
MARKOV PROCESS
MONTE CARLO METHOD
OPTICAL PROPERTIES
OSCILLATOR STRENGTHS
OSCILLATORS
REFLECTION
SILICON OXIDES
SIMULATION
SPECTRA
SUM RULES
SURFACE ENERGY
SURFACES