Tuning fulleride electronic structure and molecular ordering via variable layer index

Abstract

C60 fullerides are uniquely flexible molecular materials that exhibit a rich variety of behavior, including superconductivity and magnetism in bulk compounds, novel electronic and orientational phases in thin films, and quantum transport in a single-C60 transistor. The complexity of fulleride properties stems from the existence of many competing interactions, such as electron-electron correlations, electron-vibration coupling, and intermolecular hopping. The exact role of each interaction is controversial due to the difficulty of experimentally isolating the effects of a single interaction in the intricate fulleride materials. Here we report a unique level of control of the material properties of KxC60 ultra-thin films through well-controlled atomic layer indexing and accurate doping concentrations. Using STM techniques, we observe a series of electronic and structural phase transitions as the fullerides evolve from two-dimensional monolayers to quasi-threedimensional multilayers in the early stages of layer-by-layer growth. These results demonstrate the systematic evolution of fulleride electronic structure and molecular ordering with variable KxC60 film layer index, and shed new light on creating novel molecular structures and devices.

16 pages, 4 figures, to appear in Nature Materials

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Cited by in corpus (7)

• Dynamic Jahn-Teller effect in electron transport through single C60 molecules
• Coexistence of full-gap superconductivity and pseudogap in two-dimensional fullerides
• Visualizing molecular orientational ordering and electronic structure in CsnC60 fulleride films
• Tuning the electronic states and superconductivity in alkali fulleride films
• Evidence for Band Renormalizations in Strong-coupling Superconducting Alkali-fulleride Films
• Observation of novel gapped phases in potassium doped single layer p-terphenyl on Au (111)
• Structure and Stability of Two-Dimensional Complexes of C_20 Fullerenes