Pseudogap behavior of RuP probed by photoemission spectroscopy

TL;DR

This study investigates the electronic structure of RuP using photoemission spectroscopy, revealing a pseudogap phase with a suppressed spectral weight near the Fermi level and distinct electronic orderings from typical charge density waves.

Contribution

It provides the first detailed photoemission analysis of RuP's pseudogap behavior and clarifies the nature of its phase transitions.

Findings

Ru valence is +3 with t_{2g}^5 configuration.

Pseudogap with 2\Delta/k_BT_c ~ 3 and gap ~50 meV.

Electronic orderings differ from conventional charge density waves.

Abstract

We have studied the electronic structure of RuP and related Ru pnictides using photoemission spectroscopy. Ru 3d core-level and valence-band spectra of RuP show that the Ru valence is +3 with t_{2g}^5 configuration. The photoemisson spectral weight near the Fermi level is moderately suppressed in the pseudogap phase of RuP, consistent with the pseudogap opening of 2\Delta/k_BT_c ~ 3 (gap size \Delta ~ 50 meV and transition temperature T_c ~ 330 K). The Ru 3d peak remains sharp in the pseudogap phase and the insulating phase of RuP, suggesting that the electronic orderings responsible for the phase transitions are different from the conventional charge density wave.