Conductivity of C$^{60}$ fullerene crystals under dynamic compression up to 200 kbar

The conductivity $\sigma $ of C$^{60}$ fullerene crystals is measured under quasi-isentropic loading by a spread shock wave to a pressure of 200 kbar at the initial temperatures 293 and 77 K. A sharp increase in $\sigma $ by seven to eight orders of magnitude is detected: from $10^{-6}{-} 10^{-7}\Omega^{-1}\cdot$cm$^{-1}$ at normal conditions to $5\Omega^{-1}\cdot$cm$^{-1}$ under pressure from 100 to 200 kbar. The conductivity of samples under pressure decreases with decreasing temperature, which is characteristic of semiconductors. On pressure release, $\sigma $ regains its initial value.