Order and Disorder in C 60 and K x C 60 Multilayers: Direct Imaging with Scanning Tunneling Microscopy

Abstract

Monolayer and multilayer structures of C₆₀, a high temperature van der Waals solid, have been studied with scanning tunneling microscopy. Structures grown on GaAs(110) at 300 kelvin and at elevated temperatures show significantly different morphologies because of balances between thermodynamics and kinetics. Condensation onto stepped surfaces demonstrates preferred bonding and nucleation at step edges. Detailed studies of potassium incorporation in crystalline C₆₀ show highly ordered structures in the K₃C₆₀ metallic state but disordered non-metallic structures for high potassium concentrations.