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Title: Optical constants, band gap, and infrared-active phonons of (LaAlO{sub 3}){sub 0.3}(Sr{sub 2}AlTaO{sub 6}){sub 0.35} (LSAT) from spectroscopic ellipsometry

Abstract

Using spectroscopic ellipsometry, the authors determined the optical constants (complex dielectric function) for (LaAlO{sub 3}){sub 0.3}(Sr{sub 2}AlTaO{sub 6}){sub 0.35} (LSAT) from 0.01 to 6.5 eV. Above 0.5 eV, the data were described with a sum of two Tauc-Lorentz oscillators and two poles. A direct gap of 5.8 ± 0.1 eV was found. An Urbach tail extends to even lower photon energies and makes the crystal opaque above 4.8 eV. Using Fourier-transform infrared ellipsometry, the lattice dynamics was studied. Nine pairs of transverse/longitudinal phonons were found and attributed to disorder in the La/Sr sublattice, ordering in the Al/Ta sublattice, and two-phonon absorption.

Authors:
; ; ;  [1];  [2]; ;  [3]
  1. Department of Physics, New Mexico State University, MSC 3D, P.O. Box 30001, Las Cruces, New Mexico 88003-8001 (United States)
  2. Department of Physics, University of Texas at El Paso, El Paso, Texas 79968 (United States)
  3. Department of Physics and Fribourg Center for Nanomaterials, University of Fribourg, Chemin du Musee 3, CH-1700 Fribourg (Switzerland)
Publication Date:
OSTI Identifier:
22592849
Resource Type:
Journal Article
Journal Name:
Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films
Additional Journal Information:
Journal Volume: 34; Journal Issue: 5; Other Information: (c) 2016 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0734-2101
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; ABSORPTION; ALUMINATES; CRYSTALS; DIELECTRIC MATERIALS; ELLIPSOMETRY; FOURIER TRANSFORM SPECTROMETERS; INFRARED SPECTROMETERS; LANTHANUM COMPOUNDS; OSCILLATORS; PHONONS; PHOTONS

Citation Formats

Nunley, Timothy Nathan, Willett-Gies, Travis I., Cooke, Jacqueline A., Zollner, Stefan, Manciu, Felicia S., Marsik, Premysl, and Bernhard, Christian. Optical constants, band gap, and infrared-active phonons of (LaAlO{sub 3}){sub 0.3}(Sr{sub 2}AlTaO{sub 6}){sub 0.35} (LSAT) from spectroscopic ellipsometry. United States: N. p., 2016. Web. doi:10.1116/1.4960356.
Nunley, Timothy Nathan, Willett-Gies, Travis I., Cooke, Jacqueline A., Zollner, Stefan, Manciu, Felicia S., Marsik, Premysl, & Bernhard, Christian. Optical constants, band gap, and infrared-active phonons of (LaAlO{sub 3}){sub 0.3}(Sr{sub 2}AlTaO{sub 6}){sub 0.35} (LSAT) from spectroscopic ellipsometry. United States. https://doi.org/10.1116/1.4960356
Nunley, Timothy Nathan, Willett-Gies, Travis I., Cooke, Jacqueline A., Zollner, Stefan, Manciu, Felicia S., Marsik, Premysl, and Bernhard, Christian. 2016. "Optical constants, band gap, and infrared-active phonons of (LaAlO{sub 3}){sub 0.3}(Sr{sub 2}AlTaO{sub 6}){sub 0.35} (LSAT) from spectroscopic ellipsometry". United States. https://doi.org/10.1116/1.4960356.
@article{osti_22592849,
title = {Optical constants, band gap, and infrared-active phonons of (LaAlO{sub 3}){sub 0.3}(Sr{sub 2}AlTaO{sub 6}){sub 0.35} (LSAT) from spectroscopic ellipsometry},
author = {Nunley, Timothy Nathan and Willett-Gies, Travis I. and Cooke, Jacqueline A. and Zollner, Stefan and Manciu, Felicia S. and Marsik, Premysl and Bernhard, Christian},
abstractNote = {Using spectroscopic ellipsometry, the authors determined the optical constants (complex dielectric function) for (LaAlO{sub 3}){sub 0.3}(Sr{sub 2}AlTaO{sub 6}){sub 0.35} (LSAT) from 0.01 to 6.5 eV. Above 0.5 eV, the data were described with a sum of two Tauc-Lorentz oscillators and two poles. A direct gap of 5.8 ± 0.1 eV was found. An Urbach tail extends to even lower photon energies and makes the crystal opaque above 4.8 eV. Using Fourier-transform infrared ellipsometry, the lattice dynamics was studied. Nine pairs of transverse/longitudinal phonons were found and attributed to disorder in the La/Sr sublattice, ordering in the Al/Ta sublattice, and two-phonon absorption.},
doi = {10.1116/1.4960356},
url = {https://www.osti.gov/biblio/22592849}, journal = {Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films},
issn = {0734-2101},
number = 5,
volume = 34,
place = {United States},
year = {Thu Sep 15 00:00:00 EDT 2016},
month = {Thu Sep 15 00:00:00 EDT 2016}
}