Metallicity and Gap States in Tunneling to Fe Ousters on GaAs(llO)

Abstract

We report the characteristics of tunneling to a GaAsO 10) substrate with distinct, nanometer-size Fe clusters, as a function of distance from and size of the clusters. We show that Fe clusters of volumes ∼ 150 Å3, corresponding to ≃13 atoms, are observed to be nonmetallic with a gap at the Fermi level. Larger clusters with > 35 atoms begin to show metallic characteristics. We observe a continuum of cluster-induced gap states in tunneling to the GaAs substrate surrounding the metallic Fc clusters. The decay length of these states has a minimum decay of 3.4 Å at midgap and diverges at the valence- and conduction-band edges.KeywordsFermi LevelGaAs SubstrateTunneling CurrentDecay LengthPhysical Review LetterThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.