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Doctoral thesis
Open access
English

Topological electronic structure of few-layer and bulk van der Waals materials probed by angle-resolved photoemission

ContributorsCucchi, Irène
Defense date2020-07-02
Abstract

Van der Waals materials can be exfoliated down to atomically thin crystals, offering potential to explore physics in lower dimensionality. In this thesis, I investigated their topological electronic structure with ARPES. I studied mono-, bi- and few-layer Td-WTe2. The small size of exfoliated crystals and their air-sensitivity pose new challenges for standard ARPES setups, successfully overcome in the present study. The measurements showed the topological band gap in the monolayer, a strong Rashba splitting in the bilayer, and thickness-dependent quantum-well states up to thicknesses above 15 layers. I describe conventional measurements on the recently grown Pt2HgSe3. ARPES measurements on the bulk crystal were motivated by the prediction of a record-high topological band gap in the monolayer. This implies a weak topological insulator in the bulk with surface states only on lateral surfaces. However, ARPES measurements showed surface states on the top surface, revealing a richer topological picture.

eng
Keywords
  • Van der Waals heterostructures
  • Transition metal dichalcogenides
  • Topological materials
  • Angle-resolved photoelectron spectroscopy
  • Van Hove singularity
  • Topological surface state
  • Electronic structure
Research group
Citation (ISO format)
CUCCHI, Irène. Topological electronic structure of few-layer and bulk van der Waals materials probed by angle-resolved photoemission. 2020. doi: 10.13097/archive-ouverte/unige:142589
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Creation09/29/2020 10:21:00 AM
First validation09/29/2020 10:21:00 AM
Update time06/20/2023 2:23:49 PM
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