Coherent and incoherent bands in La and Rh doped Sr3Ir2O7

TL;DR

This study uses ARPES to explore how doping affects the electronic structure and coherence of bands in Sr3Ir2O7, revealing distinct behaviors of bands near the Fermi level and suggesting similar physics in related iridates.

Contribution

It provides new insights into the doping-dependent evolution of band coherence and spectral weights in Sr3Ir2O7, linking these findings to similar phenomena in Sr2IrO4.

Findings

Doping reduces the band gap from 0.2eV to 0.05eV.

Upper bands show quasiparticle peaks, lower bands are broad and lose weight.

Spectral weights of bands follow different periodicities.

Abstract

In Sr2IrO4 and Sr3Ir2O7, correlations, magnetism and spin-orbit coupling compete on similar energy scales, creating a new context to study metal-insulator transitions (MIT). We use here Angle-Resolved photoemission to investigate the MIT as a function of hole and electron doping in Sr3Ir2O7, obtained respectively by Ir/Rh and Sr/La substitutions. We show that there is a clear reduction as a function of doping of the gap between a lower and upper band on both sides of the Fermi level, from 0.2eV to 0.05eV. Although these two bands have a counterpart in band structure calculations, they are characterized by a very different degree of coherence. The upper band exhibits clear quasiparticle peaks, while the lower band is very broad and loses weight as a function of doping. Moreover, their ARPES spectral weights obey different periodicities, reinforcing the idea of their different nature. We argue that a very similar situation occurs in Sr2IrO4 and conclude that the physics of the two families is essentially the same.