Pressure-induced insulator to metal transition in amorphous SiO

We have observed an insulator to metal transition in amorphous silicon monoxide at a critical pressure of Pc ∼12 GPa as deduced from the temperature dependence of the electrical resistance and ir and Raman spectroscopies. X-ray scattering data indicate a disordered material at pressures below and above the transition to the metallic state and up to 30 GPa. Above Pc, dR dT becomes positive, and the ir and Raman spectra flatten, indicating delocalization of nonbonding states. The temperature dependence of the conductivity is in very good agreement with the Anderson model for amorphous materials.