Saved in:
Bibliographic Details
Main Authors: Cassol, Francesco, Gaspard, Léo, Martins, Cyril, Casula, Michele, Lenz, Benjamin
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2509.20337
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866917409816838144
author Cassol, Francesco
Gaspard, Léo
Martins, Cyril
Casula, Michele
Lenz, Benjamin
author_facet Cassol, Francesco
Gaspard, Léo
Martins, Cyril
Casula, Michele
Lenz, Benjamin
contents As a consequence of their spin-orbit entangled ground state, many $5d^{5}$ iridate materials display a peculiar double peak structure in optical transport quantities, such as absorption and conductivity. Their common interpretation is based on the presence of Hubbard subbands in the half-filled $j_{\mathrm{eff}}=1/2$ manifold. Herein, we challenge this picture, proposing a scenario based on the presence of spin-polaron (SP) quasiparticles, and assigning a dominant SP character to the first peak. We illustrate it by taking the materials Ba$_2$IrO$_4$ and Sr$_2$IrO$_4$ as paradigmatic examples, which we investigate within the dynamical mean-field theory and the self-consistent Born approximation. Both theories reproduce nontrivial features revealed by angle-resolved photoemission spectroscopy and optical transport measurements, supporting our interpretation. In the case of Sr$_2$IrO$_4$, we show how the SP scenario survives in the low-doped regime. Similar optical transport fingerprints are expected to be found in the wider class of $5d^5$ iridates and more generally in strongly correlated antiferromagnetic regimes, such as those found in cuprates.
format Preprint
id arxiv_https___arxiv_org_abs_2509_20337
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Spin-polaron fingerprints in the optical conductivity of iridates
Cassol, Francesco
Gaspard, Léo
Martins, Cyril
Casula, Michele
Lenz, Benjamin
Strongly Correlated Electrons
As a consequence of their spin-orbit entangled ground state, many $5d^{5}$ iridate materials display a peculiar double peak structure in optical transport quantities, such as absorption and conductivity. Their common interpretation is based on the presence of Hubbard subbands in the half-filled $j_{\mathrm{eff}}=1/2$ manifold. Herein, we challenge this picture, proposing a scenario based on the presence of spin-polaron (SP) quasiparticles, and assigning a dominant SP character to the first peak. We illustrate it by taking the materials Ba$_2$IrO$_4$ and Sr$_2$IrO$_4$ as paradigmatic examples, which we investigate within the dynamical mean-field theory and the self-consistent Born approximation. Both theories reproduce nontrivial features revealed by angle-resolved photoemission spectroscopy and optical transport measurements, supporting our interpretation. In the case of Sr$_2$IrO$_4$, we show how the SP scenario survives in the low-doped regime. Similar optical transport fingerprints are expected to be found in the wider class of $5d^5$ iridates and more generally in strongly correlated antiferromagnetic regimes, such as those found in cuprates.
title Spin-polaron fingerprints in the optical conductivity of iridates
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2509.20337