2007/12/04 by Yayu Wang, Ryan Yamachika, Andre Wachowiak +2
Chemistry · Engineering · Physics and Astronomy · #Advanced Physical and Chemical Molecular Interactions #Electronic structure #Fullerene #Fullerene Chemistry and Applications #Intermolecular force #Magnetism #Molecular Junctions and Nanostructures #Monolayer #Phase (matter) #Scanning tunneling microscope #Superconductivity #cond-mat.mtrl-sci #cond-mat.str-el
paper · pdf · doi:10.1038/nmat2100
16 pages, 4 figures, to appear in Nature Materials
arxiv created 2007/12/04 · openalex publication_date 2008/01/13 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
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.