Abstract
We report on a systematic electrical transport study of carbon nanowalls using both the normal metal and superconducting electrodes. The nonlinear transport and corresponding anomalous dI/dV versus bias curves below ∼2 K observed in samples with both Ti and Nb electrodes is accounted for by the formation of charge density waves due to enhanced density of states at the Fermi level at edges or extended defects. This phase competes with superconducting instability at very low temperature, as manifested by distinctive resistance-temperature behaviors and associated dV/dI characteristics observed in different samples.