Pressure-Induced B1 to B2 Phase Transition in CeN Studied by ab initio Correlation Matrix Renormalization Theory Calculations

TL;DR

This study uses correlation matrix renormalization theory to accurately predict the pressure-induced structural and electronic transition in cerium nitride, aligning well with experimental data.

Contribution

It applies CMRT to CeN to successfully model the B1 to B2 phase transition and associated electronic changes without adjustable parameters.

Findings

Predicted B1 to B2 transition with ~11% volume collapse

Electronic structure changes consistent with XPS data

Accurate equation of state matching experiments

Abstract

We apply correlation matrix renormalization theory (CMRT) to cerium nitride (CeN) under pressure. For B1 (NaCl-type) phase, CMRT gives an equation of state consistent with ambient pressure experiments. It produces electronic density-of-state (DOS) characterized by a sharp 4f quasi-particle resonance peak pinned at the Fermi level and two subbands formed by strong hybridization between the localized Ce-4f electrons and the itinerant Ce-5d and N-2p electrons below the Fermi level, consistent with XPS experiments. Upon compression, CMRT predicts a first-order B1 to B2 (CsCl-type) transition with ~11% volume collapse in agreement with experiments. Across the transition, the 4f spectral weight broadens, the 4f orbital occupancy increases, and the hybridization with conduction states enhances, signaling a crossover from partially localized to more itinerant 4f behavior. These features are in excellent agreement with experimental observations, demonstrating that CMRT provides a parameter-free description and prediction of correlation-driven structural and electronic transitions in rare-earth compounds.