Novel orientational ordering in a K-doped C$_{60}$ monolayer

ORAL

Abstract

Orientational ordering, which originates from broken rotational symmetry, is a central feature of a broad range of materials including liquid crystals, quantum magnets, and some biological systems. By doping C$_{60}$ monolayers with alkali impurities, the symmetry of C$_{60}$ molecules can be broken, opening up the possibility for unique two-dimensional molecular orientational ordering. Here we present a scanning tunneling microscopy/spectroscopy study of K$_{x}$C$_{60}$ monolayers on Au(111), $x\ge $4. We find novel orientational orderings in the C$_{60}$ monolayers at different doping levels, which coincide with strong variations in the monolayer local density of states. This demonstrates the importance of the interplay between Coulomb repulsion, electron-phonon coupling, electronic quadrupolar interactions, and direct orbital overlap in determining the behavior of fullerene nanostructures.

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Authors

  • Ryan Yamachika

  • Yayu Wang

  • Andre Wachowiak

  • Michael Grobis

  • Dung-Hai Lee

  • Amy Khoo

    • Department of Physics UC Berkeley
    • Dept of Physics, UC Berkeley

  • Steven Louie

    • Department of Physics, University of California, Berkeley \& The Molecular Foundry, Materials Sciences Division,Lawrence Berkeley National Laboratory
    • University of California at Berkeley and Lawrence Berkeley National Laboratory
    • UC Berkeley and Lawrence Berkeley National Laboratory
    • Department of Physics, University of California at Berkeley and Materials Sciences Division, LBNL
    • Dept of Physics, UC Berkeley, The Molecular Foundry, LBNL
    • University of California at Berkeley
    • Department of Physics, University of California at Berkeley and Materials Sciences Divisions, LBNL

  • Michael Crommie

    • Dept. of Physics, Dept. of Chemistry, UC Berkeley; Mat. Sci. Div, Lawrence Berkeley Natl. Lab
    • Department of Physics, University of California, Berkeley, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA