Electronic Structure of Magnetic Titanocene Dimer Molecules at a Metal Surface Measured by Scanning Tunneling Microscopy

The titanocene dimer ([Cp$_{2}$TiCl]$_{2}$, where Cp = C$_{5}$H$_{5}$ ) is an interesting magnetic molecule because it incorporates two spin-1/2 Ti atoms in an antiferromagnetic configuration. We have used cryogenic scanning tunneling microscopy to study the local electronic properties of titanocene dimer molecules adsorbed onto metal surfaces. Ordered patterns of titanocene dimmers have been observed for submonolayer coverage on Au(111). Scanning tunneling spectroscopy of the molecules shows sharp features near the Fermi energy that may be magnetic in origin.