Role of p-f Hybridization in the Metal-Non-Metal Transition of PrRu4P12

TL;DR

This study investigates the electronic state changes in PrRu4P12 during its metal-non-metal transition, highlighting the role of p-f hybridization and crystal-field schemes through diffraction experiments.

Contribution

It reveals the specific crystal-field schemes and the significance of p-f hybridization in the transition, providing new insights into the electronic structure of PrRu4P12.

Findings

Identification of two inequivalent CF schemes at Pr sites.

Evidence of p-f hybridization involving 4f^1 and 4f^3 states.

p-f hybridization influences the energy gain during the transition.

Abstract

Electronic state evolution in the metal-non-metal transition of PrRu4P12 has been studied by X-ray and polarized neutron diffraction experiments. It has been revealed that, in the low-temperature non-metallic phase, two inequivalent crystal-field (CF) schemes of Pr3+ 4f^2 electrons with Gamma_1 and Gamma_4^(2) ground states are located at Pr1 and Pr2 sites forming the bcc unit cell surrounded by the smaller and larger cubic Ru-ion sublattices, respectively. This modulated electronic state can be explained by the p-f hybridization mechanism taking two intermediate states of 4f^1 and 4f^3. The p-f hybridization effect plays an important role for the electronic energy gain in the metal-non-metal transition originated from the Fermi surface nesting.