<div class="csl-bib-body">
<div class="csl-entry">Pandeya, R. P., Shchukin, K., Falke, Y., Mussler, G., Jalil, A. R., Atodiresei, N., Hasdeo, E. H., Fedorov, A. T., Senkovskiy, B., Jansen, D., Di Santo, G., Petaccia, L., & Grüneis, A. (2025, May 22). <i>Molecular Order Induced Charge Transfer in a C₆₀-Topological Insulator Moiré Heterostructure</i> [Conference Presentation]. 247th ECS Meeting, Montreal, Canada. http://hdl.handle.net/20.500.12708/219509</div>
</div>
-
dc.identifier.uri
http://hdl.handle.net/20.500.12708/219509
-
dc.description.abstract
Buckminsterfullerene (C60) has extensively been studied due to its various exotic electronic and magnetic properties which range semiconductor in the pristine phase to metals or Mott insulators and even superconductors when C60 is doped by alkali atoms [1]. Ultrathin films of endohedral fullerenes encapsulating metal ions on highly ordered substrates further widen the range of complex and exotic electronic states [1]. While the fullerene thin film deposition on metal and insulating substrates has been explored, there are not many studies focusing on fullerene thin film deposition on topologically protected surfaces [2]. Here, we study the electronic structure of a highly ordered ultrathin fullerene film (1ML C60) deposited on the topological insulator Bi4Te3 using ARPES, Raman, and DFT methods [3]. In addition to hexagonal ordering of C60 film on Bi4Te3, the LEED analysis confirms a (4X4) reconstruction of the C60 on a (9X9) supercell of the Bi4Te3 surface. The ARPES and Fermi-surface mapping of the topologically protected surface state confirms a strong hexagonal warping deviating from the typical linearly dispersive Dirac bands [4,5]. While we observe a hole doping to the TI with C60 deposition at room temperature as rigid shifting of the Dirac point, no charge transfer at low temperature is observed. The estimated hole doping to the TI surface at room temperature is ~ 0.03 holes per C60 molecule. Due to excellent long-range ordering of C60 molecules on TI substrate, both HOMO and HOMO-1 molecular bands of C60 show a clear electron and weakly hole like band dispersions with p- and s-polarized lights, respectively. Clearly, both the molecular bands of C60 on TI surface are further splitted into at least two degenrate states due to long range hexagonal ordering. Comparison of the momentum distribution curves at C60 bands shows a rigid shift of the bands towards Fermi level with cooling consistent with observed changes in the TI surface band. Temperature dependence resonance Raman spectroscopy of the C60 pentagon pinch reveals a molecular ordering of the C60 thin film below 250 K that is reminiscent to the structural transition in bulk C60. Significant change in the Photoluminescence of C60 film at low temperature further confirms the molecular ordering at low temperature. Ab initio calculations of the reconstructed heterostructure suggest electron-doping of the C60 molecules due to tri-vacancy of the Te-terminated surface. Simulations performed for different molecular ordering suggest low electron affinity in the ground state comparison to the 300 K affecting the charge transfer at low temperatures. Our work highlights that TI surfaces are excellent substrates for the growth of highly ordered layers of fullerenes. The work shown here also paves the way for further experiments using magnetic fullerenes and superconducting C60 films grown on TI.
en
dc.language.iso
en
-
dc.subject
topological insulators
en
dc.subject
fullerene
en
dc.subject
angle-resolved photoemission
en
dc.subject
Raman
en
dc.subject
photoluminescence
en
dc.title
Molecular Order Induced Charge Transfer in a C₆₀-Topological Insulator Moiré Heterostructure
en
dc.type
Presentation
en
dc.type
Vortrag
de
dc.contributor.affiliation
University of Cologne, Germany
-
dc.contributor.affiliation
Forschungszentrum Jülich (Jülich, DE)
-
dc.contributor.affiliation
Green IT - PGI-10 - Forschungszentrum Jülich (Jülich, DE)
-
dc.contributor.affiliation
Forschungszentrum Jülich, Germany
-
dc.contributor.affiliation
Department of Physics and Material Science - University of Luxembourg (Luxembourg, LU)
-
dc.contributor.affiliation
University of Cologne
-
dc.contributor.affiliation
University of Cologne (Cologne, DE)
-
dc.contributor.affiliation
II. Institute of Physics - University of Cologne (Cologne, DE)
-
dc.contributor.affiliation
Beamline Group - Elettra Sincrotrone Trieste SCpA (Trieste, IT)
