Suppression of Metal–Insulator Transition in PrRu4P12under High Pressure Studied by Infrared Spectroscopy

Infrared reflectance spectroscopy has been used to probe the pressure evolution of metal–insulator (MI) transition in PrRu 4 P 12 up to 14 GPa. The decrease of reflectance at low temperatures, which is due to an energy gap associated with the MI transition, is almost unchanged with pressure up to 10 GPa. This decrease of reflectance, however, is strongly suppressed at 14 GPa, and an increase of reflectance is observed below 30 K. This result indicates that the MI transition of PrRu 4 P 12 has been suppressed at 14 GPa.