High-pressure electrical conductivity measurements in the copper oxides

We have measured the temperature-dependent electrical conductivity of Cu₂O at pressures up to 500 kbar and of CuO up to 700 kbar. The high-pressure phase of Cu₂O has a resistive thermal activation energy of a few meV and localization behavior below 7 K. No phase transitions were observed in CuO at pressures and temperatures up to 700 kbar and 3000 K, but its thermal activation energy decreases linearly with pressure and extrapolates to zero at about 1 Mbar.