  Using an atomic force microscope we have created nanotube junctions such as
buckles and crossings within individual single-wall metallic carbon nanotubes
connected to metallic electrodes. The electronic transport properties of these
manipulated structures show that they form electronic tunnel junctions. The
conductance shows power-law behavior as a function of bias voltage and
temperature, which can be well modeled by a Luttinger liquid model for
tunneling between two nanotube segments separated by the manipulated junction.
