Non-local Coulomb correlations in pure and electron-doped ${\mathrm{Sr}}_{2}{\mathrm{IrO}}_{4}$: spectral functions, Fermi surface and pseudogap-like spectral weight distributions from oriented cluster dynamical mean field theory

TL;DR

This paper investigates non-local Coulomb correlations and magnetic fluctuations in Sr2IrO4 using advanced cluster dynamical mean field theory, revealing insights into its spectral properties, pseudogap behavior, and effects of doping.

Contribution

It introduces a novel cluster DMFT scheme that accurately reproduces spectral functions and explains pseudogap phenomena in Sr2IrO4, highlighting the role of short-range magnetic fluctuations.

Findings

Spectral functions match ARPES data closely.

Short-range magnetic fluctuations are essential for electronic properties.

Doping leads to a cuprate-like pseudogap metallic state.

Abstract

We address the role of non-local Coulomb correlations and short-range magnetic fluctuations in the high-temperature phase of Sr$_2$IrO$_4$ within state-of-the-art spectroscopic and first-principles theoretical methods. Introducing a novel cluster dynamical mean field scheme, we compute momentum-resolved spectral functions, which we find to be in excellent agreement with angle-resolved photoemission spectra. We show that while short-range antiferromagnetic fluctuations are crucial to account for the electronic properties of the material even in the high-temperature paramagnetic phase, long-range magnetic order is not a necessary ingredient of the insulating state. Upon doping, an exotic metallic state is generated, exhibiting cuprate-like pseudo-gap spectral properties, for which we propose a surprisingly simple theoretical mechanism.