Signatures of ballistic transport in the magnetoresistance of nanostructures made of single-crystalline refractory metals

We have performed magnetotransport measurements on single-crystalline (001) W and Mo nanostructures down to 1.5 K. Due to the bulk crystalline perfection, electrons scatter mainly on the film boundaries of the nanostructures and may travel long distances without scattering. The experiments described here concern the magnetotransport with a magnetic field applied perpendicularly to the plane of the structure. We have found that the nanostructures exhibit properties which are specific to ballistic transport, such as transverse magnetic focusing, quenching of the Hall effect and negative bend resistance at low magnetic fields.