title: Bright beaches of nanoscale potassium islands on graphite in STM imaging.
abstract: We demonstrate, via scanning tunneling microscopy (STM) measurements performed at 48 K, the existence of "bright beaches" at the edges of K islands (diameter approximately 5-500 nm) on the graphite surface. The enhanced tunneling current is only observed in monolayer-high islands on graphite, and not in islands of similar geometry on top of a K monolayer film. First-principles density functional calculations and STM simulations suggest that this is an STM field effect, which appears as the positive tip attracts donated electrons back to the metallic K islands. The restored charge accumulates preferentially at the island edges.
authors.affiliation: Nanoscale Physics Research Laboratory, School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom.
authors.forename: F
authors.initials: F
authors.lastname: Yin
authors.forename: J
authors.initials: J
authors.lastname: Akola
authors.forename: P
authors.initials: P
authors.lastname: Koskinen
authors.forename: M
authors.initials: M
authors.lastname: Manninen
authors.forename: R E
authors.initials: RE
authors.lastname: Palmer