Formation of sp3-Bonded Carbon Nanostructures by Femtosecond Laser Excitation of Graphite

A scanning tunneling microscopy study and ab initio total energy calculations have identified the atomic-level structure of novel sp(3)-bonded carbon nanoscale domains formed dynamically from graphite by femtosecond-laser excitation. The structure is characterized by a pseudo sp(3)-bonding configuration that results in inward displacement of surface carbon atoms by 0.5 A in every third row along the [1(1)over bar00] orientation. This structural periodicity is unique and differs from conventional phases of diamond.