Infrared and Visible Dielectric Properties of LSAT

ORAL

Abstract

LSAT stands for the chemical formula (LaAlO$_{3})_{0.3\, }$(Sr$_{2}$AlTaO$_{6})_{0.35}$ and is a common substrate for epitaxial growth of complex metal oxides. Precise knowledge of the optical constants is useful to investigate the properties of epitaxial films grown on LSAT. We investigate the band gap and the infrared-active phonons as well as determine the dielectric function of LSAT, from the mid-IR to the deep UV (0.03 to 6.5 eV). Between 0.8 and 6.5 eV, we measured the normal-incidence transmission and the ellipsometric angles from 60 to 80 degree incidence in 2 degree steps on a J.A. Woollam variable angle of incidence ellipsometer. We also measured in the mid-IR on a rotating compensator FTIR ellipsometer. Transmission measurements show a steep rise of the absorption coefficient ($\alpha )$ between 4.6 and 4.8 eV where LSAT becomes opaque. Plotting $\alpha^{2}$ versus photon energy yields a direct band gap of 5.8 eV. An Urbach tail extends towards lower energies. The resulting dielectric function is in agreement with previous ellipsometry and minimum-deviation prism measurements. The mid-IR dielectric function shows four $\varepsilon $ peaks due to TO phonon absorption. The loss function shows four LO peaks. A fifth TO phonon was seen at 155 cm$^{-1}$ in far-IR ellipsometry. The presence of FCC ordering was also confirmed with x-ray diffraction. We will also discuss temperature dependent ellipsometry and transmission measurements.

–

Authors

  • J.A. Cooke

    NMSU

  • William Stockwell

    Logan High School, University of Tsukuba, Department of Physics, University of Texas at El Paso, El Paso, TX, Division of Engineering, Mayo Clinic, Rochester, MN, Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, Utah Valley University, University of New Mexico, Brigham Young University, Moxtek, INC, New Mexico State University, Oak Ridge National Laboratory, Oak Ridge TN 37830, USA, Los Alamos National Laboratory, Argonne National Laboratory, Embry-Riddle Aeronautical University, University of Newcastle, University of Sydney, Brigham Young University Provo, Rice University, Perimeter Institute and University of Guelph, University of Reims Champagne-Ardenne, France, Texas A&M University, University of Illinois at Urbana-Champaign, University of Valencia, Spain, None, University of Texas at El Paso, Universidad Simon Bolivar, Universidad Autonoma de Ciudad Juarez, Brigham Young University - Provo, Morgan High School - Morgan, UT, Utah State University, University of Tsukaba, Chemistry Research Center, US Air Force Academy, USAFA, JILA, University of Colorado Boulder, Department of Physics, Border Biomedical Research Center, University of Texas at El Paso, El Paso, TX, Department of Orthopedics, Mayo Clinic, Rochester, MN, Colorado State University, National Research Tomsk Polytechnic University \& New Mexico State University,, National Institute of Standards and Technology Center for Neutron Research, Oak Ridge National Laboratory, Huazhong University of Science and Technology, U of Utah, NMSU, Division of Engineering, Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, Chemical Science Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA, INM - Leibniz Institute for New Materials, Saarbrucken, Germany, Department of Physics, The University of Texas at El Paso, El Paso, Texas, 7996, UTEP, Arizona State University, The University of Texas at El Paso, none, National Renewable Energy Laboratory, Division of Engineering, Department of Neurologic Surgery, Mayo Clinic, Department of Physics, Border Biomedical Research Center, University of Texas at El Paso, Division of Engineering, Mayo Clinic, Department of Neurologic Surgery, Mayo Clinic, Department of Physics & Astronomy, Texas A&M University, Commerce,TX-75428, USA., INFN, Sezione di Pisa, Largo Pontecorvo 3, 56127 Pisa, Italy, Texas A&M University Commerce, Commerce, Texas-75429, Department of Physics and Astronomy, Texas A&M University-Commerce, Commerce, Texas 75429, USA, Cyclotron Institute, Texas A&M University, College Station, Texas 77843, USA, Department of Physics, University of Texas at El Paso, University of Delaware, IIT INDORE, UT AUSTIN, Idaho Accelerator Center, Brigham Young University, Physics and Astronomy, Univesidad de Guanajuato, Fermilab, École Polytechnique Fédérale de Lausanne, RadiaSoft, LLC, Weber State University, University of Texas at Dallas, National High Magnetic Field Laboratory, University of Texas Southwestern Medical Center, University of Alabama in Huntsville, Marshall Space Flight Center, NASA, Howard University

  • William Stockwell

    Logan High School, University of Tsukuba, Department of Physics, University of Texas at El Paso, El Paso, TX, Division of Engineering, Mayo Clinic, Rochester, MN, Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, Utah Valley University, University of New Mexico, Brigham Young University, Moxtek, INC, New Mexico State University, Oak Ridge National Laboratory, Oak Ridge TN 37830, USA, Los Alamos National Laboratory, Argonne National Laboratory, Embry-Riddle Aeronautical University, University of Newcastle, University of Sydney, Brigham Young University Provo, Rice University, Perimeter Institute and University of Guelph, University of Reims Champagne-Ardenne, France, Texas A&M University, University of Illinois at Urbana-Champaign, University of Valencia, Spain, None, University of Texas at El Paso, Universidad Simon Bolivar, Universidad Autonoma de Ciudad Juarez, Brigham Young University - Provo, Morgan High School - Morgan, UT, Utah State University, University of Tsukaba, Chemistry Research Center, US Air Force Academy, USAFA, JILA, University of Colorado Boulder, Department of Physics, Border Biomedical Research Center, University of Texas at El Paso, El Paso, TX, Department of Orthopedics, Mayo Clinic, Rochester, MN, Colorado State University, National Research Tomsk Polytechnic University \& New Mexico State University,, National Institute of Standards and Technology Center for Neutron Research, Oak Ridge National Laboratory, Huazhong University of Science and Technology, U of Utah, NMSU, Division of Engineering, Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, Chemical Science Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA, INM - Leibniz Institute for New Materials, Saarbrucken, Germany, Department of Physics, The University of Texas at El Paso, El Paso, Texas, 7996, UTEP, Arizona State University, The University of Texas at El Paso, none, National Renewable Energy Laboratory, Division of Engineering, Department of Neurologic Surgery, Mayo Clinic, Department of Physics, Border Biomedical Research Center, University of Texas at El Paso, Division of Engineering, Mayo Clinic, Department of Neurologic Surgery, Mayo Clinic, Department of Physics & Astronomy, Texas A&M University, Commerce,TX-75428, USA., INFN, Sezione di Pisa, Largo Pontecorvo 3, 56127 Pisa, Italy, Texas A&M University Commerce, Commerce, Texas-75429, Department of Physics and Astronomy, Texas A&M University-Commerce, Commerce, Texas 75429, USA, Cyclotron Institute, Texas A&M University, College Station, Texas 77843, USA, Department of Physics, University of Texas at El Paso, University of Delaware, IIT INDORE, UT AUSTIN, Idaho Accelerator Center, Brigham Young University, Physics and Astronomy, Univesidad de Guanajuato, Fermilab, École Polytechnique Fédérale de Lausanne, RadiaSoft, LLC, Weber State University, University of Texas at Dallas, National High Magnetic Field Laboratory, University of Texas Southwestern Medical Center, University of Alabama in Huntsville, Marshall Space Flight Center, NASA, Howard University

  • William Stockwell

    Logan High School, University of Tsukuba, Department of Physics, University of Texas at El Paso, El Paso, TX, Division of Engineering, Mayo Clinic, Rochester, MN, Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, Utah Valley University, University of New Mexico, Brigham Young University, Moxtek, INC, New Mexico State University, Oak Ridge National Laboratory, Oak Ridge TN 37830, USA, Los Alamos National Laboratory, Argonne National Laboratory, Embry-Riddle Aeronautical University, University of Newcastle, University of Sydney, Brigham Young University Provo, Rice University, Perimeter Institute and University of Guelph, University of Reims Champagne-Ardenne, France, Texas A&M University, University of Illinois at Urbana-Champaign, University of Valencia, Spain, None, University of Texas at El Paso, Universidad Simon Bolivar, Universidad Autonoma de Ciudad Juarez, Brigham Young University - Provo, Morgan High School - Morgan, UT, Utah State University, University of Tsukaba, Chemistry Research Center, US Air Force Academy, USAFA, JILA, University of Colorado Boulder, Department of Physics, Border Biomedical Research Center, University of Texas at El Paso, El Paso, TX, Department of Orthopedics, Mayo Clinic, Rochester, MN, Colorado State University, National Research Tomsk Polytechnic University \& New Mexico State University,, National Institute of Standards and Technology Center for Neutron Research, Oak Ridge National Laboratory, Huazhong University of Science and Technology, U of Utah, NMSU, Division of Engineering, Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, Chemical Science Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA, INM - Leibniz Institute for New Materials, Saarbrucken, Germany, Department of Physics, The University of Texas at El Paso, El Paso, Texas, 7996, UTEP, Arizona State University, The University of Texas at El Paso, none, National Renewable Energy Laboratory, Division of Engineering, Department of Neurologic Surgery, Mayo Clinic, Department of Physics, Border Biomedical Research Center, University of Texas at El Paso, Division of Engineering, Mayo Clinic, Department of Neurologic Surgery, Mayo Clinic, Department of Physics & Astronomy, Texas A&M University, Commerce,TX-75428, USA., INFN, Sezione di Pisa, Largo Pontecorvo 3, 56127 Pisa, Italy, Texas A&M University Commerce, Commerce, Texas-75429, Department of Physics and Astronomy, Texas A&M University-Commerce, Commerce, Texas 75429, USA, Cyclotron Institute, Texas A&M University, College Station, Texas 77843, USA, Department of Physics, University of Texas at El Paso, University of Delaware, IIT INDORE, UT AUSTIN, Idaho Accelerator Center, Brigham Young University, Physics and Astronomy, Univesidad de Guanajuato, Fermilab, École Polytechnique Fédérale de Lausanne, RadiaSoft, LLC, Weber State University, University of Texas at Dallas, National High Magnetic Field Laboratory, University of Texas Southwestern Medical Center, University of Alabama in Huntsville, Marshall Space Flight Center, NASA, Howard University