Dielectric breakdown phenomena accompanied by characteristic time delay and subsequent negative differential resistance effect have been observed for typical one-dimensional (1D) Mott insulators, ${\mathrm{Sr}}_2{\mathrm{CuO}}_3$ and ${\mathrm{SrCuO}}_2.$ In the both compounds, the threshold electric-field for the breakdown, defined as a field above which the differential resistance becomes negative, has been found to increase exponentially with decreasing temperature. This result is similar to the case of charge-density-wave depinning, and indicates the collective nature of charge dynamics in these 1D systems. The electric-field dependence of the delay time is analyzed in terms of a phenomenological model.

• Received 9 December 1999

DOI:https://doi.org/10.1103/PhysRevB.62.7015