Electronic state of PrFe4P12 under high pressure probed by infrared spectroscopy

Abstract The infrared reflectivity spectra under pressure have been measured for filled-skutterudite PrFe 4 P 12 . In the far-infrared (FIR) region, four phonon peaks became prominent and shifted monotonically for higher energy side under pressure. The pressure induced insulator phase at low temperature was stable up to 18 GPa without any large structural change through the metal–insulator transition.