Fingerprints of Mott and Slater gaps in the core-level photoemission spectra of antiferromagnetic iridates

2024/04/19 by Nakagawa, K., Hariki, A., Okauchi, T. +15
#FOS: Physical sciences #Strongly Correlated Electrons (cond-mat.str-el)

paper · doi:10.48550/arxiv.2404.12646

Abstract

We present Ir 4f core-level hard-x-ray photoemission spectroscopy (HAXPES) experiments conducted across antiferromagnetic (AFM) ordering transition in Ruddlesden-Popper iridates Sr₂IrO₄ and Sr₃Ir₂O₇. The Ir 4f spectra exhibit distinct changes between the AFM and paramagnetic (PM) phases, with the spectral difference I_PM-I_AFM showing a contrasting behavior in the two compounds. By employing computational simulations using the local-density approximation combined with the dynamical mean-field theory method, we elucidate that I_PM-I_AFM primary reflects the Slater or Mott-Hubbard character of the AFM insulating state rather than material specific details. This sensitivity to fine low-energy electronic structure arises from the dependence of charge-transfer responses to the sudden creation of a localized core hole on both metal-insulator transitions and long-range AFM ordering. Our result broadens the applications of core-level HAXPES as a tool for characterization of electronic structure.

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