Optical constants, band gap, and infrared-active phonons of (LaAlO₃)0.3(Sr₂AlTaO₆)0.35 (LSAT) from spectroscopic ellipsometry
- Nunley, Timothy Nathan Department of Physics, New Mexico State University, Las Cruces,New Mexico USA
- Willett-Gies, Travis I. Department of Physics, New Mexico State University, Las Cruces,New Mexico USA
- Cooke, Jacqueline A. Department of Physics, New Mexico State University, Las Cruces,New Mexico USA
- Manciu, Felicia S. Department of Physics, University of Texas at El Paso, El Paso, USA
- Marsik, Premysl Department of Physics and Fribourg Center for Nanomaterials, University of Fribourg, Switzerland
- Bernhard, Christian Department of Physics and Fribourg Center for Nanomaterials, University of Fribourg, Switzerland
- Zollner, Stefan Department of Physics, New Mexico State University, Las Cruces,New Mexico USA
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04.08.2016
Published in:
- Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films. - 2016, vol. 34, no. 5, p. 051507
English
Using spectroscopic ellipsometry, the authors determined the optical constants (complex dielectric function) for (LaAlO₃)0.3(Sr₂AlTaO₆) 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
- Faculty
- Faculté des sciences et de médecine
- Department
- Département de Physique
- Language
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- English
- Classification
- Physics
- License
- License undefined
- Identifiers
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- RERO DOC 278695
- DOI 10.1116/1.4960356
- Persistent URL
- https://folia.unifr.ch/unifr/documents/305252
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