Abstract
The current-voltage characteristics of layered organic crystals () follow the power law with a large exponent (e.g., 8.4 at 0.29 K for ) over a wide range of currents in the low-temperature insulating state. The power-law characteristics are attributed to electric field-induced unbinding of electron-hole pairs that are thermally excited in the background of the two-dimensional charge order. The magnitude of crossover electric fields from Ohmic to the power-law characteristics indicates that the electron-electron Coulomb interaction is significantly long-ranged: The screening length is greater than 10 molecule sites.
- Received 27 October 2005
DOI:https://doi.org/10.1103/PhysRevLett.96.136602
©2006 American Physical Society