Abstract

Using low-temperature scanning tunnelling microscopy we
investigate the conductance of adatoms and molecules on surfaces.
Going beyond the tunnelling range, we explore closer tip-sample
distances in the contact regime where currents of several
microamperes are passed through the junction.  The talk will
address the role of molecular structure and bonding, switching of planar
molecules, and the emission of light from contacts.  An unusual
conductance quantization at single magnetic atoms between various
electrodes will also be presented.