Delocalization Transition of a Classical Two-Dimensional Coulomb Lattice

The dielectric-plasma transition of the two-dimensional Coulomb gas, suitably mapped onto a delocalization transition, is investigated by molecular-dynamics simulations. The threshold temperature $T_1$ for electrical conduction falls well below the temperature $T_2$ associated with a marked peak in the specific heat; $T_2$ is close to the mean-field prediction for the Kosterlitz-Thouless transition, $\frac{k_{\mathrm{B}}{T}_2}{e^2}=\frac{1}{4}$.