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

Abstract

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.

Pressure suppression of unconventional charge-density-wave state in PrRu4P12studied by optical conductivity

“…3 The usual Kramers-Kronig (KK) transform 28,29 was applied to the R 0 (ω) to obtain the complex refractive indexn(ω).n(ω) was then used to derive the reflectance spectrum, R d (ω), that was expected in a DAC, taking into account the refractive index of diamond (2.4) as previously discussed. 16,17,19,20 The R d (ω) data at P =0 in Fig. 1(a) are the results of this analysis.…”

“…σ(ω) of a sample at high pressure was obtained from the analysis of a reflectance spectrum, R(ω), measured with a diamond anvil cell (DAC). [16][17][18][19][20] A pair of diamond anvils with 0.6 mm culet diameter and a metal gasket (stainless steel 301) were used to seal the sample, pressure transmitting medium, and small ruby pieces used to monitor the pressure via its fluorescence. 17 A flat, asgrown surface of a single crystal sample 2 was closely attached on the culet surface of the anvil, which was of type IIa with low density of impurities.…”