HIGH-FIELD FORMATION OF LINEAR CARBON CHAINS AND ATOMIC CLUSTERS

Abstract

Linear forms of carbon are important in a wide variety of applications, ranging from highly conducting interconnects to field emission materials. By methods of field ion microscopy (FIM) and mass-spectrometry, it was revealed that linear carbon chains were present at the surface of carbon fibers after high-voltage treatment. The carbon chains attached to the specimen tips were produced in situ in a field ion microscope by unraveling of nanofibers using low-temperature evaporation in electric fields of the order of 1011 Vm-1. The unraveling of graphite is possible due to the ultimate strength of the monoatomic carbon chain. The maximum force before failure of carbon chains at 0 K is 7.916 nN at a strain of 0.19 and the ideal tensile strength is equal to 252.1 GPa. Molecular dynamics simulations and high resolution FIM experiments are performed to assess the evaporation of atomic chains under high-field conditions. One can conclude that ions are field evaporated from a graphite surface initially in linear cluster forms, which decompose mostly into smaller atomic clusters and individual ions because of the ultrahigh-temperature excitation during unraveling.