Origin of charge density wave formation in insulators from a high resolution photoemission study of BaIrO3

TL;DR

This study uses high-resolution photoemission spectroscopy to explore the origin of charge density wave formation in BaIrO3, revealing localized states, a soft gap opening, and the influence of magnetic interactions on electronic structure.

Contribution

It provides new insights into the role of magnetic interactions in CDW formation in insulators, highlighting the interplay between ferromagnetism and charge density waves in BaIrO3.

Findings

Localized density of states at Fermi level near room temperature

Vanishing of localized states and gap opening at CDW transition

Magnetic interactions influence electronic structure, not Coulomb repulsion

Abstract

We investigate the origin of charge density wave (CDW) formation in insulators by studying BaIrO3 using high resolution (1.4 meV) photoemission spectroscopy. The spectra reveal the existence of localized density of states at the Fermi level in the vicinity of room temperature. These localized states are found to vanish as the temperature is lowered thereby, opening a soft gap at the Fermi level, as a consequence of CDW transition. In addition, the energy dependence of the spectral density of states reveals the importance of magnetic interactions, rather than well-known Coulomb repulsion effect, in determining the electronic structure thereby implying a close relationship between ferromagnetism and CDW observed in this compound. Also, Ba core level spectra surprisingly exhibit an unusual behavior prior to CDW transition.