Phase-coherent transport in a mesoscopic few-layer graphite wire

Four-terminal magnetotransport measurements have been performed on a mesoscopic graphite wire with a thickness of about seven graphene layers in which the carrier density can be tuned via the field effect using a back gate and in-plane gates. The conductance measured as a function of back gate voltage and temperature can be well described by the simple two-band model. Measurements of Shubnikov-de Haas oscillations agree well with the parameters extracted at zero magnetic field with the help of the model. Measurements of the weak localization correction to the conductivity and conductance fluctuations confirm the mesoscopic character of electronic transport and allow to estimate the phase-coherence length to be of the order of the wire length (several microns) at the lowest temperatures. The results are compatible with electron-electron interactions being responsible for decoherence at the lowest temperatures.