Local distortion induced metal-to-insulator phase transition in PrRu4P12 -: art. no. 036403

Extended x-ray absorption fine structure (EXAFS) experiments have been carried out on PrRu4P12 and PrOs4P12 to study the metal-to-insulator (MI) phase transition in PrRu4P12. No Pr displacement was observed across the MI transition temperature from the EXAFS data. Instead, our EXAFS data clearly show that a Ru displacement is associated with this MI transition. The very high Debye temperature for the Ru-P bond (Theta(D)=690 K) suggests that a slight rotation/displacement of relatively rigid RuP6 octahedra leads to this small Ru displacement, which accompanies the MI transition at 62 K in PrRu4P12.