Threshold transport properties of self-assembled 1D chains of conducting nanoparticles

A new self-assembling technique is used to grow a single chain of graphite nanoparticles which bridges the gap between two microelectrodes. Collective charge transport in such chains is studied experimentally. At low temperatures we observe a voltage-driven phase transition from a static insulating state, in which the current ($I$) is {\it exponentially} small, to a dynamic conducting state in which the current scales as $I \sim (V-V_{T})^{\zeta}$. The threshold voltage $V_{T}$ is much bigger than the single particle Coulomb gap voltage due to collective charge pinning in the random potential. The threshold decreases linearly with increasing temperature.