THz conductivity measurement of MnSi

ORAL

Abstract

We present measurements of the low-frequency optical conductivity of a thin film of MnSi, using time-domain terahertz spectroscopy. At low temperatures and low frequencies, we extract the DC resistivity, scattering life time and plasma frequency from a Drude fit. We obtain a value of $\omega_p\simeq1.0$ eV, which can be used to estimate the renormalization coefficient through comparison with band theory. At higher temperatures, a deviation from Drude behavior is observed, suggesting a loss of quasi-particle coherence. In the region of low temperatures and high frequencies, we see evidence for a crossover to the anomalous power law dependence observed by Mena \textit{et al.}\footnote{F.P. Mena \textit{et al.} Phys. Rev. B. {\bf67}, 241101(R) (2003).} As the temperature increases, the anomalous frequency dependence becomes more pronounced, and the plasma frequency inferred from a Drude fit increases dramatically. Above T$\approx 50$ K, $\sigma_2(\omega)$ develops a negative slope that is inconsistent with both a Drude model and the anomalous power law observed earlier, indicating a sharp pseudogap in the conductivity spectrum.

–

Authors

  • Laleh Mohtashemi

    Simon Fraser University

  • Amir Farahani

    Simon Fraser University

  • C. Andreoiu

    University of Washington, Centre for Organic Photonics and Electronics, School of Chemistry and Molecular Biosciences, University of Queensland, Centre for Organic Photonics and Electronics, School of Mathematics and Physics, University of Queensland, Department of Physics, Simon Fraser University, Dalhousie University, Faculty of Mathematics, University of Waterloo, Department of Physics, McMaster University, SLAC National Accelerator Laboratory, Stanford University, Stanford University, IFW-Dresden, Northern Illinois University, University of British Columbia, University of Michigan, Simon Fraser University, Institute for Quantum Computing, University of Waterloo, Washington State University, The University of British Columbia, The Weizmann Institute of Science, Oregon State University, University of Massachusetts Lowell, Aixtron Ltd., Cornell University, TRIUMF, Society of Physics Students, Western Washington University, Department of Physics and Astronomy, Washington State University, University of Portland, Pacific University, University of Idaho, Department of Physics, University of Washington, Emory University, SFU, Arizona State University, Research Centre J\"ulich, University of Victoria, EPM, \'Ecole Polytechnique de Montr\'eal (EPM), Technical U of Denmark, Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, Department of Physics, Portland State University, Portland, OR 97201, Department of Physics, Oregon State University, Corvallis, OR 97331, Department of Physics, Cornell University, Ithaca, NY 14853, Linfield College, Portland State University, University of British Columbia Physics and Astronomy, University of British Columbia Chemistry, Max Planck Institute for Polymer Research, Simon Fraser, Los Alamos National Lab, Los Alamos, McGill University, Los Alamos National Laboratory, University of Cambridge, CSNSM-IN2P3-CNRS, University of Manitobia, Univ. of British Columbia and TRIUMF, Ruprecht-Karls-Universitat and MPI and TRIUMF, Westfaelische Wilhelms-Universitaet, Univ. of Manitoba and TRIUMF, Tenische Universitaet Muenchen and TRIUMF, Simon Fraser Univ. and TRIUMF, University of British Columbia, TRIUMF, Ruprecht-Karls-Universit\"at Heidelberg, Max Planck Institute, TRIUMF, Westf\"alische Wilhelms-Universit\"at, TRIUMF, Johannes Gutenberg-Universit\"at Mainz, Ruprecht-Karls-Universit\"at Heidelberg, Univerity of Manitoba, TRIUMF, Simon Fraser University, TRIUMF, TRIUMF \& University of Manitoba, College of William and Mary, Universidad Autonoma de San Luis Potosi, University of Maryland, University of Manitoba, UBC, Texas A\&M, University of Kentucky, Georgia Institute of Technology, University of Guelph, St. Mary's University

  • Theodore L. Monchesky

    Dalhousie University

  • J. Steven Dodge

    Simon Fraser University, Department of Physics, Simon Fraser University