Insight into Topological Insulators from Infrared Spectroscopy

ORAL

Abstract

Topological insulators are certain band-insulator compounds that exhibit a new phase of quantum matter with inverted insolating energy gap. As a result, these bulk insulators have conducting states on the surface. This new state of matter is a consequence of strong spin-orbit coupling in these materials. We use infrared reflectance spectroscopy to probe electrodynamics of charge carriers at different temperatures and we conduct magneto-optical spectroscopy experiments to probe magneto-electric coupling. We present findings on several second-generation Bi-based topological insulators at temperatures ranging from 10 to 300 K and in magnetic fields up to 18 T. In addition, we discuss the charge inhomogeneities in these novel materials.

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Authors

  • N. Stojilovic

    University of Wisconsin Oshkosh

  • Kurt Baughman

    Center for Nanoscale Materials, Argonne National Lab, Argonne, Illinois, Department of Physics and Astronomy, Ohio University, Athens, Ohio, Ohio University, Los Alamos Nationa Laboratory, National Taiwan University, University of Hamburg, Trinity College, Dublin, Serbian Academy of Sciences and Arts, Institute for Multidisciplinary Research, University of Belgrade, National High Magnetic Field Laboratory, Brookhaven National Laboratory, The University of Akron, NQPI, Physics and Astronomy Dept., Ohio University, GNS \& MANA Satellite, CEMES, CNRS, IMRE, A*STAR, Nanoscale and Quantum Phenomena Institute (NQPI), Physics and Astronomy Dept., Ohio University, Nanoscale and Quantum Phenomena Institute, and Department of Physics \& Astronomy, Ohio University, Athens, OH 45701, CEMES, CNRS, Toulouse, France, Nanoscale and Quantum Phenomena Institute, and Department of Physics \& Astronomy, Ohio University, Athens, OH, NQPI, and Department of Physics \& Astronomy, Ohio University, Athens, OH, NQPI Dept of Physics and astronomy Ohio University, Naval Research Labs, Washington DC 20375, John Carroll University, Lawrence Livermore National Laboratory, The Ohio State University Department of Physics, Nanoscale and Quantum Phenomena Institute, Department of Physics and Astronomy, Ohio University, Athens, Ohio, Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, National High Magnetic Field Laboratory, Tallahassee, University of Wisconsin Oshkosh, Wittenberg University, NQPI, Ohio University; CNM Argonne National Laboratory, APS, CNM, Argonne National Laboratory, Ohio University, Athens 45701, USA, None, Dept. of Physics, Hiram College, Physics Department, Cleveland State University, Flash Center for Computational Science, University of Chicago, Center for Energy Research, University of California San Diego; Lawrence Livermore National Laboratory, Ohio Northern University, Ohio University Zanesville

  • Kurt Baughman

    Center for Nanoscale Materials, Argonne National Lab, Argonne, Illinois, Department of Physics and Astronomy, Ohio University, Athens, Ohio, Ohio University, Los Alamos Nationa Laboratory, National Taiwan University, University of Hamburg, Trinity College, Dublin, Serbian Academy of Sciences and Arts, Institute for Multidisciplinary Research, University of Belgrade, National High Magnetic Field Laboratory, Brookhaven National Laboratory, The University of Akron, NQPI, Physics and Astronomy Dept., Ohio University, GNS \& MANA Satellite, CEMES, CNRS, IMRE, A*STAR, Nanoscale and Quantum Phenomena Institute (NQPI), Physics and Astronomy Dept., Ohio University, Nanoscale and Quantum Phenomena Institute, and Department of Physics \& Astronomy, Ohio University, Athens, OH 45701, CEMES, CNRS, Toulouse, France, Nanoscale and Quantum Phenomena Institute, and Department of Physics \& Astronomy, Ohio University, Athens, OH, NQPI, and Department of Physics \& Astronomy, Ohio University, Athens, OH, NQPI Dept of Physics and astronomy Ohio University, Naval Research Labs, Washington DC 20375, John Carroll University, Lawrence Livermore National Laboratory, The Ohio State University Department of Physics, Nanoscale and Quantum Phenomena Institute, Department of Physics and Astronomy, Ohio University, Athens, Ohio, Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, National High Magnetic Field Laboratory, Tallahassee, University of Wisconsin Oshkosh, Wittenberg University, NQPI, Ohio University; CNM Argonne National Laboratory, APS, CNM, Argonne National Laboratory, Ohio University, Athens 45701, USA, None, Dept. of Physics, Hiram College, Physics Department, Cleveland State University, Flash Center for Computational Science, University of Chicago, Center for Energy Research, University of California San Diego; Lawrence Livermore National Laboratory, Ohio Northern University, Ohio University Zanesville

  • Kurt Baughman

    Center for Nanoscale Materials, Argonne National Lab, Argonne, Illinois, Department of Physics and Astronomy, Ohio University, Athens, Ohio, Ohio University, Los Alamos Nationa Laboratory, National Taiwan University, University of Hamburg, Trinity College, Dublin, Serbian Academy of Sciences and Arts, Institute for Multidisciplinary Research, University of Belgrade, National High Magnetic Field Laboratory, Brookhaven National Laboratory, The University of Akron, NQPI, Physics and Astronomy Dept., Ohio University, GNS \& MANA Satellite, CEMES, CNRS, IMRE, A*STAR, Nanoscale and Quantum Phenomena Institute (NQPI), Physics and Astronomy Dept., Ohio University, Nanoscale and Quantum Phenomena Institute, and Department of Physics \& Astronomy, Ohio University, Athens, OH 45701, CEMES, CNRS, Toulouse, France, Nanoscale and Quantum Phenomena Institute, and Department of Physics \& Astronomy, Ohio University, Athens, OH, NQPI, and Department of Physics \& Astronomy, Ohio University, Athens, OH, NQPI Dept of Physics and astronomy Ohio University, Naval Research Labs, Washington DC 20375, John Carroll University, Lawrence Livermore National Laboratory, The Ohio State University Department of Physics, Nanoscale and Quantum Phenomena Institute, Department of Physics and Astronomy, Ohio University, Athens, Ohio, Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, National High Magnetic Field Laboratory, Tallahassee, University of Wisconsin Oshkosh, Wittenberg University, NQPI, Ohio University; CNM Argonne National Laboratory, APS, CNM, Argonne National Laboratory, Ohio University, Athens 45701, USA, None, Dept. of Physics, Hiram College, Physics Department, Cleveland State University, Flash Center for Computational Science, University of Chicago, Center for Energy Research, University of California San Diego; Lawrence Livermore National Laboratory, Ohio Northern University, Ohio University Zanesville

  • Kurt Baughman

    Center for Nanoscale Materials, Argonne National Lab, Argonne, Illinois, Department of Physics and Astronomy, Ohio University, Athens, Ohio, Ohio University, Los Alamos Nationa Laboratory, National Taiwan University, University of Hamburg, Trinity College, Dublin, Serbian Academy of Sciences and Arts, Institute for Multidisciplinary Research, University of Belgrade, National High Magnetic Field Laboratory, Brookhaven National Laboratory, The University of Akron, NQPI, Physics and Astronomy Dept., Ohio University, GNS \& MANA Satellite, CEMES, CNRS, IMRE, A*STAR, Nanoscale and Quantum Phenomena Institute (NQPI), Physics and Astronomy Dept., Ohio University, Nanoscale and Quantum Phenomena Institute, and Department of Physics \& Astronomy, Ohio University, Athens, OH 45701, CEMES, CNRS, Toulouse, France, Nanoscale and Quantum Phenomena Institute, and Department of Physics \& Astronomy, Ohio University, Athens, OH, NQPI, and Department of Physics \& Astronomy, Ohio University, Athens, OH, NQPI Dept of Physics and astronomy Ohio University, Naval Research Labs, Washington DC 20375, John Carroll University, Lawrence Livermore National Laboratory, The Ohio State University Department of Physics, Nanoscale and Quantum Phenomena Institute, Department of Physics and Astronomy, Ohio University, Athens, Ohio, Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, National High Magnetic Field Laboratory, Tallahassee, University of Wisconsin Oshkosh, Wittenberg University, NQPI, Ohio University; CNM Argonne National Laboratory, APS, CNM, Argonne National Laboratory, Ohio University, Athens 45701, USA, None, Dept. of Physics, Hiram College, Physics Department, Cleveland State University, Flash Center for Computational Science, University of Chicago, Center for Energy Research, University of California San Diego; Lawrence Livermore National Laboratory, Ohio Northern University, Ohio University Zanesville

  • Kurt Baughman

    Center for Nanoscale Materials, Argonne National Lab, Argonne, Illinois, Department of Physics and Astronomy, Ohio University, Athens, Ohio, Ohio University, Los Alamos Nationa Laboratory, National Taiwan University, University of Hamburg, Trinity College, Dublin, Serbian Academy of Sciences and Arts, Institute for Multidisciplinary Research, University of Belgrade, National High Magnetic Field Laboratory, Brookhaven National Laboratory, The University of Akron, NQPI, Physics and Astronomy Dept., Ohio University, GNS \& MANA Satellite, CEMES, CNRS, IMRE, A*STAR, Nanoscale and Quantum Phenomena Institute (NQPI), Physics and Astronomy Dept., Ohio University, Nanoscale and Quantum Phenomena Institute, and Department of Physics \& Astronomy, Ohio University, Athens, OH 45701, CEMES, CNRS, Toulouse, France, Nanoscale and Quantum Phenomena Institute, and Department of Physics \& Astronomy, Ohio University, Athens, OH, NQPI, and Department of Physics \& Astronomy, Ohio University, Athens, OH, NQPI Dept of Physics and astronomy Ohio University, Naval Research Labs, Washington DC 20375, John Carroll University, Lawrence Livermore National Laboratory, The Ohio State University Department of Physics, Nanoscale and Quantum Phenomena Institute, Department of Physics and Astronomy, Ohio University, Athens, Ohio, Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, National High Magnetic Field Laboratory, Tallahassee, University of Wisconsin Oshkosh, Wittenberg University, NQPI, Ohio University; CNM Argonne National Laboratory, APS, CNM, Argonne National Laboratory, Ohio University, Athens 45701, USA, None, Dept. of Physics, Hiram College, Physics Department, Cleveland State University, Flash Center for Computational Science, University of Chicago, Center for Energy Research, University of California San Diego; Lawrence Livermore National Laboratory, Ohio Northern University, Ohio University Zanesville

  • Kurt Baughman

    Center for Nanoscale Materials, Argonne National Lab, Argonne, Illinois, Department of Physics and Astronomy, Ohio University, Athens, Ohio, Ohio University, Los Alamos Nationa Laboratory, National Taiwan University, University of Hamburg, Trinity College, Dublin, Serbian Academy of Sciences and Arts, Institute for Multidisciplinary Research, University of Belgrade, National High Magnetic Field Laboratory, Brookhaven National Laboratory, The University of Akron, NQPI, Physics and Astronomy Dept., Ohio University, GNS \& MANA Satellite, CEMES, CNRS, IMRE, A*STAR, Nanoscale and Quantum Phenomena Institute (NQPI), Physics and Astronomy Dept., Ohio University, Nanoscale and Quantum Phenomena Institute, and Department of Physics \& Astronomy, Ohio University, Athens, OH 45701, CEMES, CNRS, Toulouse, France, Nanoscale and Quantum Phenomena Institute, and Department of Physics \& Astronomy, Ohio University, Athens, OH, NQPI, and Department of Physics \& Astronomy, Ohio University, Athens, OH, NQPI Dept of Physics and astronomy Ohio University, Naval Research Labs, Washington DC 20375, John Carroll University, Lawrence Livermore National Laboratory, The Ohio State University Department of Physics, Nanoscale and Quantum Phenomena Institute, Department of Physics and Astronomy, Ohio University, Athens, Ohio, Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, National High Magnetic Field Laboratory, Tallahassee, University of Wisconsin Oshkosh, Wittenberg University, NQPI, Ohio University; CNM Argonne National Laboratory, APS, CNM, Argonne National Laboratory, Ohio University, Athens 45701, USA, None, Dept. of Physics, Hiram College, Physics Department, Cleveland State University, Flash Center for Computational Science, University of Chicago, Center for Energy Research, University of California San Diego; Lawrence Livermore National Laboratory, Ohio Northern University, Ohio University Zanesville

  • Kurt Baughman

    Center for Nanoscale Materials, Argonne National Lab, Argonne, Illinois, Department of Physics and Astronomy, Ohio University, Athens, Ohio, Ohio University, Los Alamos Nationa Laboratory, National Taiwan University, University of Hamburg, Trinity College, Dublin, Serbian Academy of Sciences and Arts, Institute for Multidisciplinary Research, University of Belgrade, National High Magnetic Field Laboratory, Brookhaven National Laboratory, The University of Akron, NQPI, Physics and Astronomy Dept., Ohio University, GNS \& MANA Satellite, CEMES, CNRS, IMRE, A*STAR, Nanoscale and Quantum Phenomena Institute (NQPI), Physics and Astronomy Dept., Ohio University, Nanoscale and Quantum Phenomena Institute, and Department of Physics \& Astronomy, Ohio University, Athens, OH 45701, CEMES, CNRS, Toulouse, France, Nanoscale and Quantum Phenomena Institute, and Department of Physics \& Astronomy, Ohio University, Athens, OH, NQPI, and Department of Physics \& Astronomy, Ohio University, Athens, OH, NQPI Dept of Physics and astronomy Ohio University, Naval Research Labs, Washington DC 20375, John Carroll University, Lawrence Livermore National Laboratory, The Ohio State University Department of Physics, Nanoscale and Quantum Phenomena Institute, Department of Physics and Astronomy, Ohio University, Athens, Ohio, Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, National High Magnetic Field Laboratory, Tallahassee, University of Wisconsin Oshkosh, Wittenberg University, NQPI, Ohio University; CNM Argonne National Laboratory, APS, CNM, Argonne National Laboratory, Ohio University, Athens 45701, USA, None, Dept. of Physics, Hiram College, Physics Department, Cleveland State University, Flash Center for Computational Science, University of Chicago, Center for Energy Research, University of California San Diego; Lawrence Livermore National Laboratory, Ohio Northern University, Ohio University Zanesville

  • Kurt Baughman

    Center for Nanoscale Materials, Argonne National Lab, Argonne, Illinois, Department of Physics and Astronomy, Ohio University, Athens, Ohio, Ohio University, Los Alamos Nationa Laboratory, National Taiwan University, University of Hamburg, Trinity College, Dublin, Serbian Academy of Sciences and Arts, Institute for Multidisciplinary Research, University of Belgrade, National High Magnetic Field Laboratory, Brookhaven National Laboratory, The University of Akron, NQPI, Physics and Astronomy Dept., Ohio University, GNS \& MANA Satellite, CEMES, CNRS, IMRE, A*STAR, Nanoscale and Quantum Phenomena Institute (NQPI), Physics and Astronomy Dept., Ohio University, Nanoscale and Quantum Phenomena Institute, and Department of Physics \& Astronomy, Ohio University, Athens, OH 45701, CEMES, CNRS, Toulouse, France, Nanoscale and Quantum Phenomena Institute, and Department of Physics \& Astronomy, Ohio University, Athens, OH, NQPI, and Department of Physics \& Astronomy, Ohio University, Athens, OH, NQPI Dept of Physics and astronomy Ohio University, Naval Research Labs, Washington DC 20375, John Carroll University, Lawrence Livermore National Laboratory, The Ohio State University Department of Physics, Nanoscale and Quantum Phenomena Institute, Department of Physics and Astronomy, Ohio University, Athens, Ohio, Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, National High Magnetic Field Laboratory, Tallahassee, University of Wisconsin Oshkosh, Wittenberg University, NQPI, Ohio University; CNM Argonne National Laboratory, APS, CNM, Argonne National Laboratory, Ohio University, Athens 45701, USA, None, Dept. of Physics, Hiram College, Physics Department, Cleveland State University, Flash Center for Computational Science, University of Chicago, Center for Energy Research, University of California San Diego; Lawrence Livermore National Laboratory, Ohio Northern University, Ohio University Zanesville

  • Kurt Baughman

    Center for Nanoscale Materials, Argonne National Lab, Argonne, Illinois, Department of Physics and Astronomy, Ohio University, Athens, Ohio, Ohio University, Los Alamos Nationa Laboratory, National Taiwan University, University of Hamburg, Trinity College, Dublin, Serbian Academy of Sciences and Arts, Institute for Multidisciplinary Research, University of Belgrade, National High Magnetic Field Laboratory, Brookhaven National Laboratory, The University of Akron, NQPI, Physics and Astronomy Dept., Ohio University, GNS \& MANA Satellite, CEMES, CNRS, IMRE, A*STAR, Nanoscale and Quantum Phenomena Institute (NQPI), Physics and Astronomy Dept., Ohio University, Nanoscale and Quantum Phenomena Institute, and Department of Physics \& Astronomy, Ohio University, Athens, OH 45701, CEMES, CNRS, Toulouse, France, Nanoscale and Quantum Phenomena Institute, and Department of Physics \& Astronomy, Ohio University, Athens, OH, NQPI, and Department of Physics \& Astronomy, Ohio University, Athens, OH, NQPI Dept of Physics and astronomy Ohio University, Naval Research Labs, Washington DC 20375, John Carroll University, Lawrence Livermore National Laboratory, The Ohio State University Department of Physics, Nanoscale and Quantum Phenomena Institute, Department of Physics and Astronomy, Ohio University, Athens, Ohio, Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, National High Magnetic Field Laboratory, Tallahassee, University of Wisconsin Oshkosh, Wittenberg University, NQPI, Ohio University; CNM Argonne National Laboratory, APS, CNM, Argonne National Laboratory, Ohio University, Athens 45701, USA, None, Dept. of Physics, Hiram College, Physics Department, Cleveland State University, Flash Center for Computational Science, University of Chicago, Center for Energy Research, University of California San Diego; Lawrence Livermore National Laboratory, Ohio Northern University, Ohio University Zanesville

  • Kurt Baughman

    Center for Nanoscale Materials, Argonne National Lab, Argonne, Illinois, Department of Physics and Astronomy, Ohio University, Athens, Ohio, Ohio University, Los Alamos Nationa Laboratory, National Taiwan University, University of Hamburg, Trinity College, Dublin, Serbian Academy of Sciences and Arts, Institute for Multidisciplinary Research, University of Belgrade, National High Magnetic Field Laboratory, Brookhaven National Laboratory, The University of Akron, NQPI, Physics and Astronomy Dept., Ohio University, GNS \& MANA Satellite, CEMES, CNRS, IMRE, A*STAR, Nanoscale and Quantum Phenomena Institute (NQPI), Physics and Astronomy Dept., Ohio University, Nanoscale and Quantum Phenomena Institute, and Department of Physics \& Astronomy, Ohio University, Athens, OH 45701, CEMES, CNRS, Toulouse, France, Nanoscale and Quantum Phenomena Institute, and Department of Physics \& Astronomy, Ohio University, Athens, OH, NQPI, and Department of Physics \& Astronomy, Ohio University, Athens, OH, NQPI Dept of Physics and astronomy Ohio University, Naval Research Labs, Washington DC 20375, John Carroll University, Lawrence Livermore National Laboratory, The Ohio State University Department of Physics, Nanoscale and Quantum Phenomena Institute, Department of Physics and Astronomy, Ohio University, Athens, Ohio, Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, National High Magnetic Field Laboratory, Tallahassee, University of Wisconsin Oshkosh, Wittenberg University, NQPI, Ohio University; CNM Argonne National Laboratory, APS, CNM, Argonne National Laboratory, Ohio University, Athens 45701, USA, None, Dept. of Physics, Hiram College, Physics Department, Cleveland State University, Flash Center for Computational Science, University of Chicago, Center for Energy Research, University of California San Diego; Lawrence Livermore National Laboratory, Ohio Northern University, Ohio University Zanesville

  • Kurt Baughman

    Center for Nanoscale Materials, Argonne National Lab, Argonne, Illinois, Department of Physics and Astronomy, Ohio University, Athens, Ohio, Ohio University, Los Alamos Nationa Laboratory, National Taiwan University, University of Hamburg, Trinity College, Dublin, Serbian Academy of Sciences and Arts, Institute for Multidisciplinary Research, University of Belgrade, National High Magnetic Field Laboratory, Brookhaven National Laboratory, The University of Akron, NQPI, Physics and Astronomy Dept., Ohio University, GNS \& MANA Satellite, CEMES, CNRS, IMRE, A*STAR, Nanoscale and Quantum Phenomena Institute (NQPI), Physics and Astronomy Dept., Ohio University, Nanoscale and Quantum Phenomena Institute, and Department of Physics \& Astronomy, Ohio University, Athens, OH 45701, CEMES, CNRS, Toulouse, France, Nanoscale and Quantum Phenomena Institute, and Department of Physics \& Astronomy, Ohio University, Athens, OH, NQPI, and Department of Physics \& Astronomy, Ohio University, Athens, OH, NQPI Dept of Physics and astronomy Ohio University, Naval Research Labs, Washington DC 20375, John Carroll University, Lawrence Livermore National Laboratory, The Ohio State University Department of Physics, Nanoscale and Quantum Phenomena Institute, Department of Physics and Astronomy, Ohio University, Athens, Ohio, Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, National High Magnetic Field Laboratory, Tallahassee, University of Wisconsin Oshkosh, Wittenberg University, NQPI, Ohio University; CNM Argonne National Laboratory, APS, CNM, Argonne National Laboratory, Ohio University, Athens 45701, USA, None, Dept. of Physics, Hiram College, Physics Department, Cleveland State University, Flash Center for Computational Science, University of Chicago, Center for Energy Research, University of California San Diego; Lawrence Livermore National Laboratory, Ohio Northern University, Ohio University Zanesville