Pandeya, R. P., Shchukin, K. P., Falke, Y., Mussler, G., Jalil, A. R., Atodiresei, N., Hasdeo, E. H., Fedorov, A., Senkovskiy, B., Jansen, D., Di Santo, G., Petaccia, L., & Grüneis, A. (2025). Molecular Order Induced Charge Transfer in a C₆₀-Topological Insulator Moiré Heterostructure. Nano Letters, 25(3), 1220–1225. https://doi.org/10.1021/acs.nanolett.4c06294
We synthesized and spectroscopically investigated monolayer (ML) C₆₀ on the topological insulator (TI) Bi₄Te₃. This C₆₀/Bi₄Te₃ heterostructure is characterized by an excellent translational order in a novel (4 × 4) C₆₀ superstructure on a (9 × 9) cell of Bi₄Te₃. Angle-resolved photoemission spectroscopy (ARPES) of C₆₀/Bi₄Te₃ reveals that ML C₆₀ accepts electrons from the TI at room temperature, but no charge transfer occurs at low temperatures. This temperature-dependent doping is further investigated by Raman spectroscopy, photoluminescence (PL), and calculations of C₆₀/Bi₄Te₃. At low temperatures, Raman spectroscopy and PL show a dramatic intensity increase of the C₆₀-related signal, suggesting a transition to a rotationally ordered state. Calculations explain the charge transfer by C₆₀ adsorption to Bi₄Te₃ surface defects. The temperature dependence of the charge transfer is attributed to the orientational order of C₆₀. The electron affinity of C₆₀ increases at low temperatures due to the freezing of the rotational motion.
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Research Areas:
Materials Characterization: 25% Surfaces and Interfaces: 50% Structure-Property Relationsship: 25%
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