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Insensitivity of the striped charge orders in IrTe2 to alkali surface doping implies their structural origin


Rumo, Maxime; Pulkkinen, Aki; Salzmann, Björn; Kremer, Geoffroy; Hildebrand, Baptiste; Ma, Ke Yuan; von Rohr, Fabian O; Nicholson, Christopher W; Jaouen, Thomas; Monney, Claude (2021). Insensitivity of the striped charge orders in IrTe2 to alkali surface doping implies their structural origin. Physical Review Materials, 5(7):074002.

Abstract

We present a combined angle-resolved photoemission spectroscopy and low-energy electron diffraction (LEED) study of the prominent transition metal dichalcogenide IrTe2 upon potassium (K) deposition on its surface. Pristine IrTe2 undergoes a series of charge-ordered phase transitions below room temperature that are characterized by the formation of stripes of Ir dimers of different periodicities. Supported by density functional theory calculations, we first show that the K atoms dope the topmost IrTe2 layer with electrons, therefore strongly decreasing the work function and shifting only the electronic surface states towards higher binding energy. We then follow the evolution of its electronic structure as a function of temperature across the charge-ordered phase transitions and observe that their critical temperatures are unchanged for K coverages of 0.13 and 0.21 monolayer. Using LEED we also confirm that the periodicity of the related stripe phases is unaffected by the K doping. We surmise that the charge-ordered phase transitions of IrTe2 are robust against electron surface doping, because of its metallic nature at all temperatures, and due to the importance of structural effects in stabilizing charge order in IrTe2.

Abstract

We present a combined angle-resolved photoemission spectroscopy and low-energy electron diffraction (LEED) study of the prominent transition metal dichalcogenide IrTe2 upon potassium (K) deposition on its surface. Pristine IrTe2 undergoes a series of charge-ordered phase transitions below room temperature that are characterized by the formation of stripes of Ir dimers of different periodicities. Supported by density functional theory calculations, we first show that the K atoms dope the topmost IrTe2 layer with electrons, therefore strongly decreasing the work function and shifting only the electronic surface states towards higher binding energy. We then follow the evolution of its electronic structure as a function of temperature across the charge-ordered phase transitions and observe that their critical temperatures are unchanged for K coverages of 0.13 and 0.21 monolayer. Using LEED we also confirm that the periodicity of the related stripe phases is unaffected by the K doping. We surmise that the charge-ordered phase transitions of IrTe2 are robust against electron surface doping, because of its metallic nature at all temperatures, and due to the importance of structural effects in stabilizing charge order in IrTe2.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Department of Chemistry
Dewey Decimal Classification:540 Chemistry
Scopus Subject Areas:Physical Sciences > General Materials Science
Physical Sciences > Physics and Astronomy (miscellaneous)
Uncontrolled Keywords:Physics and Astronomy (miscellaneous), General Materials Science
Language:English
Date:2 July 2021
Deposited On:09 Feb 2022 08:03
Last Modified:26 Feb 2024 02:47
Publisher:American Physical Society
ISSN:2475-9953
OA Status:Green
Publisher DOI:https://doi.org/10.1103/physrevmaterials.5.074002
Project Information:
  • : FunderSNSF
  • : Grant IDPP00P2_170597
  • : Project TitleInvestigating the ultrafast dynamics of Mott correlations
  • Content: Accepted Version