Atomic-Scale Observation of Topological Vortices in the Incommensurate Charge Density Wave of 2H-TaSe2

Seongjoon Lim, Jaewook Kim, Choongjae Won, Sang Wook Cheong

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

It has been only recently realized that topological vortices associated with structural distortions or ordered spins are rather common in numerous materials where long-range interactions are not dominant. Incommensurate modulations that frequently occur in charge density wave (CDW) materials are often understood in terms of discommensurations with a periodic phase shift. The accumulation of a one-dimensional (1D) phase shift can result in, for example, CDW dislocations in 2H-TaSe2 with incommensurate CDW (I-CDW). Since any atomic-scale experimental investigation of CDW dislocations in 2H-TaSe2 has been lacking, we have performed the atomic-scale observation of 2H-TaSe2 with I-CDW, stabilized with Pd intercalation or strain, with scanning probe microscopy, and unveiled the existence of topological Z6 or Z4 vortices with topologically protected 2D winding movements of atomic displacement vectors. The discovery opens the ubiquitous nature of topological vortex domains and a new avenue to explore new facets of various incommensurate modulations or discommensurations.

Original languageEnglish (US)
Pages (from-to)4801-4808
Number of pages8
JournalNano Letters
Volume20
Issue number7
DOIs
StatePublished - Jul 8 2020

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • General Chemistry
  • General Materials Science
  • Condensed Matter Physics
  • Mechanical Engineering

Keywords

  • 2H-TaSe
  • CDW
  • STM
  • domain boundaries
  • incommensuration
  • topological vortices
  • transition metal dichalcogenides

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