Statics and dynamics of multivalley charge density waves in Sb(111)

Anton Tamtögl, Patrick Kraus-Füreder, Michael Mayrhofer-Reinhartshuber, Giorgio Benedek, Marco Bernasconi, Daniele Dragoni, Davide Campi, Wolfgang E. Ernst

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Charge density waves (CDWs), periodic modulations of the charge density, are among the most abundant and non-trivial ordered phases in condensed matter. Here we demonstrate the occurrence of multi-valley charge density waves (MV-CDW) on the semimetal Sb(111), a phenomenon previously observed at semiconductor surface inversion layers. The topological nature of the pocket surface states in Sb(111) ensures perfect nesting conditions giving rise to sharp peaks in helium atom scattering (HAS) diffraction spectra. The peculiar temperature dependence permits to distinctly associate the diffraction peaks with surface electron and hole-pocket states due to the non-trivial surface electronic band structure known from recent experimental data and present ab-initio calculations. Inelastic HAS spectra, besides providing the surface phonon dispersion curves in agreement with density functional perturbation theory calculations, reveal two additional dispersion curves of elementary excitations in the gap well below Rayleigh waves. They are attributed to collective excitations of the quasi-commensurate MV-CDWs associated with the surface electron M-pocket states at the Fermi level. These findings suggest that HAS can be regarded as a choice spectroscopy for the investigation of surface electronic excitations in the THz domain, opening up a new window for the search of collective phases at surfaces.
Original languageEnglish
Article number28
Journalnpj Quantum Materials
Volume4
Issue number1
DOIs
Publication statusPublished - 12 Jun 2019

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helium atoms
scattering
metalloids
Rayleigh waves
curves
elementary excitations
electronics
diffraction
excitation
valleys
electrons
perturbation theory
occurrences
inversions
modulation
temperature dependence
spectroscopy

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

Statics and dynamics of multivalley charge density waves in Sb(111). / Tamtögl, Anton; Kraus-Füreder, Patrick; Mayrhofer-Reinhartshuber, Michael; Benedek, Giorgio; Bernasconi, Marco; Dragoni, Daniele; Campi, Davide; Ernst, Wolfgang E.

In: npj Quantum Materials, Vol. 4, No. 1, 28, 12.06.2019.

Research output: Contribution to journalArticleResearchpeer-review

Tamtögl, Anton ; Kraus-Füreder, Patrick ; Mayrhofer-Reinhartshuber, Michael ; Benedek, Giorgio ; Bernasconi, Marco ; Dragoni, Daniele ; Campi, Davide ; Ernst, Wolfgang E. / Statics and dynamics of multivalley charge density waves in Sb(111). In: npj Quantum Materials. 2019 ; Vol. 4, No. 1.
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