First-principles study of a single C60 cluster adsorbed on KBr(1 0 0)

Atomic and electronic structure of the C60 monomer adsorbed KBr(1 0 0) surface has been studied by using density-functional theory calculations. We found that a single C60 cluster favors an adsorption configuration where a hexagon ring of C60 adsorbs atop the surface K atom. The energy gain by adsorption is as small as 0.37 eV, and the resulting structural modifications of the C60 cluster and the KBr(1 0 0) substrate are negligible. Calculated density of states and charge characters indicate that this structure is stabilized by a weak interaction between the p-orbitals of interfacial C and Br atoms. The present calculations are found to be useful in understanding the structural properties of a close-packed C60 monolayer phase grown on KBr(1 0 0) in a recent atomic force microscopy study.