Abstract
C60 fullerides are uniquely flexible molecular materials that exhibit a rich variety of behaviour1, including superconductivity and magnetism in bulk compounds2,3, novel electronic and orientational phases in thin films4,5,6,7,8,9,10 and quantum transport in a single-C60 transistor11. 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 owing 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 ultrathin films through well-controlled atomic layer indexing and accurate doping concentrations. Using scanning tunnelling microscope techniques, we observe a series of electronic and structural phase transitions as the fullerides evolve from two-dimensional monolayers to quasi-three-dimensional 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 provide essential information for the development of new molecular structures and devices.
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References
Gunnarsson, O. Alkali-Doped Fullerides: Narrow-Band Solids with Unusual Properties (World Scientific, Singapore, 2004).
Hebard, A. F. et al. Superconductivity at 18 K in potassium-doped C60 . Nature 350, 600–601 (1991).
Allemand, P. M. et al. Organic molecular soft ferromagnetism in a fullerene C60 . Science 253, 301–303 (1991).
Tjeng, L. H. et al. Development of the electronic structure in a K-doped C60 monolayer on a Ag(111) surface. Solid State Commun. 103, 31–35 (1997).
Hou, J. G. et al. Surface science—Topology of two-dimensional C60 domains. Nature 409, 304–305 (2001).
Yang, W. L. et al. Band structure and Fermi surface of electron-doped C60 monolayers. Science 300, 303–307 (2003).
Brouet, V. et al. Orientation-dependent C60 electronic structures revealed by photoemission spectroscopy. Phys. Rev. Lett. 93, 197601 (2004).
Wachowiak, A. et al. Visualization of the molecular Jahn–Teller effect in an insulating K4C60 monolayer. Science 310, 468–470 (2005).
Pai, W. W., Hsu, C. L., Lin, K. C., Sin, L. Y. & Tang, T. B. Characterization and control of molecular ordering on adsorbate-induced reconstructed surfaces. Appl. Surf. Sci. 241, 194–198 (2005).
Wang, Y. et al. Novel orientational ordering and reentrant metallicity in KxC60 monolayers for 3<x<5. Phys. Rev. Lett. 99, 086402 (2007).
Park, H. et al. Nanomechanical oscillations in a single-C60 transistor. Nature 407, 57–60 (2000).
Grobis, M., Wachowiak, A., Yamachika, R. & Crommie, M. F. Tuning negative differential resistance in a molecular film. Appl. Phys. Lett. 86, 204102 (2005).
Schiessling, J. et al. Bulk and surface charge states of K3C60 . Phys. Rev. B 71, 165420 (2005).
Gunnarsson, O. Superconductivity in fullerides. Rev. Mod. Phys. 69, 575–606 (1997).
Yamachika, R., Grobis, M., Wachowiak, A. & Crommie, M. F. Controlled atomic doping of a single C60 molecule. Science 304, 281–284 (2004).
Lu, X. H., Grobis, M., Khoo, K. H., Louie, S. G. & Crommie, M. F. Spatially mapping the spectral density of a single C60 molecule. Phys. Rev. Lett. 90, 096802 (2003).
Chakravarty, S., Gelfand, M. P. & Kivelson, S. Electronic correlation effects and superconductivity in doped fullerenes. Science 254, 970–974 (1991).
Lu, J. P. Metal–insulator transitions in degenerate Hubbard models and AxC60 . Phys. Rev. B 49, 5687–5690 (1994).
Gunnarsson, O., Koch, E. & Martin, R. M. Mott transition in degenerate Hubbard models: Application to doped fullerenes. Phys. Rev. B 54, 11026–11029 (1996).
Fabrizio, M. & Tosatti, E. Nonmagnetic molecular Jahn–Teller Mott insulators. Phys. Rev. B 55, 13465–13472 (1997).
Han, J. E., Gunnarsson, O. & Crespi, V. H. Strong superconductivity with local Jahn–Teller phonons in C60 solids. Phys. Rev. Lett. 90, 167006 (2003).
Cox, D. M., Trevor, D. J., Reichmann, K. C. & Kaldor, A. C60La—a deflated soccer ball. J. Am. Chem. Soc. 108, 2457–2458 (1986).
Antropov, V. P., Gunnarsson, O. & Jepsen, O. Coulomb integrals and model Hamiltonians for C60 . Phys. Rev. B 46, 13647–13650 (1992).
Martin, R. L. & Ritchie, J. P. Coulomb and exchange interactions in C60n−. Phys. Rev. B 48, 4845–4849 (1993).
Lof, R. W., Vanveenendaal, M. A., Koopmans, B., Jonkman, H. T. & Sawatzky, G. A. Band-gap, excitons, and Coulomb interaction in solid C60 . Phys. Rev. Lett. 68, 3924–3927 (1992).
Hesper, R., Tjeng, L. H. & Sawatzky, G. A. Strongly reduced band gap in a correlated insulator in close proximity to a metal. Europhys. Lett. 40, 177–182 (1997).
Pederson, M. R. & Quong, A. A. Polarizabilities, charge states, and vibrational modes of isolated fullerene molecules. Phys. Rev. B 46, 13584–13591 (1992).
Lammert, P. E., Rokhsar, D. S., Chakravarty, S., Kivelson, S. & Salkola, M. I. Metallic screening and correlation effects in superconducting fullerenes. Phys. Rev. Lett. 74, 996–999 (1995).
Meinders, M. B. J., Tjeng, L. H. & Sawatzky, G. A. Comment on “C 1s autoionization study of electron hopping rates in solid C60”. Phys. Rev. Lett. 73, 2937 (1994).
Han, J. E., Koch, E. & Gunnarsson, O. Metal–insulator transitions: Influence of lattice structure, Jahn–Teller effect, and Hund’s rule coupling. Phys. Rev. Lett. 84, 1276–1279 (2000).
Hebard, A. F., Haddon, R. C., Fleming, R. M. & Kortan, A. R. Deposition and characterization of fullerene films. Appl. Phys. Lett. 59, 2109–2111 (1991).
Koch, E., Gunnarsson, O. & Martin, R. M. Filling dependence of the Mott transition in the degenerate Hubbard model. Phys. Rev. B 60, 15714–15720 (1999).
Gunnarsson, O., Satpathy, S., Jepsen, O. & Andersen, O. K. Orientation of C60 clusters in solids. Phys. Rev. Lett. 67, 3002–3005 (1991).
Ramirez, A. P. Geometrically frustrated matter—Magnets to molecules. Mater. Res. Soc. Bull. 30, 447–451 (2005).
Acknowledgements
This work was supported in part by NSF Grant EIA-0205641 and by the Director, Office of Energy Research, Office of Basic Energy Science, Division of Material Sciences and Engineering, US Department of Energy under contract No. DE-AC03-76SF0098. Y.W. acknowledges a research fellowship from the Miller Institute for Basic Research in Science.
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Wang, Y., Yamachika, R., Wachowiak, A. et al. Tuning fulleride electronic structure and molecular ordering via variable layer index. Nature Mater 7, 194–197 (2008). https://doi.org/10.1038/nmat2100
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DOI: https://doi.org/10.1038/nmat2100
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