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