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Holographic imaging of the complex charge density wave order parameter

Publié dansPhysical Review Research, vol. 1, no. 3, 033114
Date de publication2019
Résumé

The charge density wave (CDW) in solids is a collective ground state combining lattice distortions and charge ordering. It is defined by a complex order parameter with an amplitude and a phase. The amplitude and wavelength of the charge modulation are readily accessible to experiment. However, accurate measurements of the corresponding phase are significantly more challenging. Here we combine reciprocal and real space information to map the full complex order parameter based on topographic scanning tunneling microscopy (STM) images. Our technique overcomes limitations of Fourier space based techniques to achieve distinct amplitude and phase images with high spatial resolution. Applying this analysis to transition metal dichalcogenides provides striking evidence that their CDWs consist of three individual unidirectional charge modulations whose ordering vectors are connected by the fundamental rotational symmetry of the crystalline lattice. Spatial variations in the relative phases of these three modulations account for the different CDW contrasts often observed in STM topographic images. Phase images further reveal topological defects and discommensurations, a singularity predicted by theory for a nearly commensurate CDW. Such precise real space mapping of the complex order parameter provides a powerful tool for a deeper understanding of the CDW ground state whose formation mechanisms remain largely unclear.

Mots-clés
  • Charge density wave
  • Scanning tunneling microscopy
  • Transition metal dichalcogenide
Groupe de recherche
Financement
  • Swiss National Science Foundation - 182652
  • Swiss National Science Foundation - 147607
Citation (format ISO)
PASZTOR, Arpad et al. Holographic imaging of the complex charge density wave order parameter. In: Physical Review Research, 2019, vol. 1, n° 3, p. 033114. doi: 10.1103/PhysRevResearch.1.033114
Fichiers principaux (1)
Article (Published version)
Identifiants
ISSN du journal2643-1564
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Informations techniques

Création19/11/2019 20:52:00
Première validation19/11/2019 20:52:00
Heure de mise à jour15/03/2023 18:24:46
Changement de statut15/03/2023 18:24:46
Dernière indexation12/02/2024 13:07:18
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