Charge density wave formation in multi-band systems

ORAL

Abstract

Charge and spin density waves are among the most abundant low-temperature ordered phases in condensed matter. The Fermi surface topology is widely believed to determine the ordering direction. However, several recent experimental and theoretical studies show that nesting is only one out of various other driving forces behind these instabilities. We use Raman scattering to demonstrate in which way an enhanced electron-lattice interaction can contribute to or even determine the selection of the ordering vector in the model charge density wave (CDW) system ErTe$_3$ and other rare-earth tri-tellurides. In our joint experimental and theoretical study we exploit the symmetry properties of the electron-photon and electron-phonon coupling vertex and establish a relation between the selection rules of the electronic light scattering spectra and the enhanced electron-phonon coupling in the vicinity of band degeneracy points. The proposal shown here for CDW formation, may be of more general relevance in multi-band systems for driving phase transitions into other broken-symmetry ground states. For example, the iron-based superconductors exhibit a similar phenomenology close to the intersection points of the backfolded electron bands.

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Authors

  • Rudi Hackl

    • Walther Meissner Institut, 85748 Garching, Germany

  • Hans-Martin Eiter

    • Walther Meissner Institut, 85748 Garching, Germany

  • Michela Lavagnini

    • Walther Meissner Institut, 85748 Garching, Germany

  • Elizabeth Nowadnick

    • Stanford University, Stanford CA 94305, USA
    • Stanford University and SLAC National Accelerator Laboratory

  • Alexander F. Kemper

    • Stanford University, Stanford CA 94305, USA

  • Thomas Devereaux

    • SLAC National Acceleratory Laboratory
    • Stanford University, Stanford CA 94305, USA
    • Stanford Institute of Materials and Energy Sciences, SLAC NATIONAL ACCELERATOR LABORATORY 2575 Sand Hill Road, Menlo Park, CA 94025
    • Stanford Institute for Materials and Energy Science, SLAC National Accelerator Laboratory
    • SLAC National Accelerator Lab and Stanford University
    • Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory

  • Jiun-Haw Chu

    • Stanford University, Stanford CA 94305, USA

  • James G. Analytis

    • Stanford University, Stanford CA 94305, USA

  • Ian Fisher

    • Stanford University, Stanford CA 94305, USA
    • Stanford University
    • Stanford Univeristy

  • C. Mirri

    • ETH Zurich, 8093 Zurich, Switzerland
    • Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
    • ETH Zurich