Search for metallization in benzene to 209 GPa pressure

Abstract

It is anticipated that all insulating materials will become metallic under sufficiently high pressure. Insulating compounds containing a high concentration of hydrogen may metalize at lower pressures than pure hydrogen, perhaps exhibiting superconductivity at relatively high temperatures. Recent electronic structure calculations indicate that benzene C₆H₆ may enter a metallic, molecular state under pressure in the region 180–200 GPa. Optical transmission studies, however, fail to reveal metallic behavior in benzene to 209 GPa at ambient temperature. A partial Raman spectrum of benzene was measured to 43.9 GPa.

Keywords:

• metallization
• high pressure
• diamond-anvil cell
• molecular solid
• optical transition
• Raman scattering

Acknowledgements

The authors would like to thank Roald Hoffmann and Neil Ashcroft for helpful discussions. Thanks are due the referee for helpful comments on the validity of the diamond vibron calibration. This research was supported by the National Science Foundation under Grant DMR-1104742.