Phase-coherent transport measured in a side-gated mesoscopic graphite wire

We investigate the magnetotransport properties of a thin graphite wire resting on a silicon oxide substrate. The electric field effect is demonstrated with back and side gate electrodes. We study the conductance fluctuations as a function of gate voltage, magnetic field, and temperature. The phase coherence length extracted from weak localization is larger than the wire width even at the lowest carrier densities, making the system effectively one dimensional. We find that the phase coherence length increases linearly with the conductivity, suggesting that at 1.7 K dephasing originates mainly from electron-electron interactions.