Dispersion kinks from electronic correlations in an unconventional iron-based superconductor

Fuente: arXiv
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Main Authors: Chang, Ming-Hua, Backes, Steffen, Lu, Donghui, Gauthier, Nicolas, Hashimoto, Makoto, Chen, Guan-Yu, Wen, Hai-Hu, Mo, Sung-Kwan, Valenti, Roser, Pfau, Heike
Format: Preprint
Published: 2024
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author Chang, Ming-Hua
Backes, Steffen
Lu, Donghui
Gauthier, Nicolas
Hashimoto, Makoto
Chen, Guan-Yu
Wen, Hai-Hu
Mo, Sung-Kwan
Valenti, Roser
Pfau, Heike
author_facet Chang, Ming-Hua
Backes, Steffen
Lu, Donghui
Gauthier, Nicolas
Hashimoto, Makoto
Chen, Guan-Yu
Wen, Hai-Hu
Mo, Sung-Kwan
Valenti, Roser
Pfau, Heike
contents The attractive interaction in conventional BCS superconductors is provided by a bosonic mode. However, the pairing glue of most unconventional superconductors is unknown. The effect of electron-boson coupling is therefore extensively studied in these materials. A key signature are dispersion kinks that can be observed in the spectral function as abrupt changes in velocity and lifetime of quasiparticles. Here, we show the existence of two kinks in the unconventional iron-based superconductor RbFe$_2$As$_2$ using angle-resolved photoemission spectroscopy (ARPES) and dynamical mean field theory (DMFT). In addition, we observe the formation of a Hubbard band multiplet due to the combination of Coulomb interaction and Hund's rule coupling in this multiorbital systems. We demonstrate that the two dispersion kinks are a consequence of these strong many-body interactions. This interpretation is in line with a growing number of theoretical predictions for kinks in various general models of correlated materials. Our results provide a unifying link between iron-based superconductors and different classes of correlated, unconventional superconductors such as cuprates and heavy-fermion materials.
format Preprint
id arxiv_https___arxiv_org_abs_2410_23044
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Dispersion kinks from electronic correlations in an unconventional iron-based superconductor
Chang, Ming-Hua
Backes, Steffen
Lu, Donghui
Gauthier, Nicolas
Hashimoto, Makoto
Chen, Guan-Yu
Wen, Hai-Hu
Mo, Sung-Kwan
Valenti, Roser
Pfau, Heike
Strongly Correlated Electrons
Superconductivity
The attractive interaction in conventional BCS superconductors is provided by a bosonic mode. However, the pairing glue of most unconventional superconductors is unknown. The effect of electron-boson coupling is therefore extensively studied in these materials. A key signature are dispersion kinks that can be observed in the spectral function as abrupt changes in velocity and lifetime of quasiparticles. Here, we show the existence of two kinks in the unconventional iron-based superconductor RbFe$_2$As$_2$ using angle-resolved photoemission spectroscopy (ARPES) and dynamical mean field theory (DMFT). In addition, we observe the formation of a Hubbard band multiplet due to the combination of Coulomb interaction and Hund's rule coupling in this multiorbital systems. We demonstrate that the two dispersion kinks are a consequence of these strong many-body interactions. This interpretation is in line with a growing number of theoretical predictions for kinks in various general models of correlated materials. Our results provide a unifying link between iron-based superconductors and different classes of correlated, unconventional superconductors such as cuprates and heavy-fermion materials.
title Dispersion kinks from electronic correlations in an unconventional iron-based superconductor
topic Strongly Correlated Electrons
Superconductivity
url https://arxiv.org/abs/2410.23044