UTe$_2$: a narrow band superconductor

Fuente: arXiv
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Main Authors: Sundermann, Martin, Okauchi, Takaki, Ito, Naoki, Christovam, Denise S., Marino, Andrea, Takegami, Daiskue, Golskovskii, Andrei, Rosa, Priscila F. S., Kuneš, Jan, Fujimori, Shin ichi, Tjeng, Liu Hao, Severing, Andrea, Hariki, Atsushi
Format: Preprint
Published: 2025
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author Sundermann, Martin
Okauchi, Takaki
Ito, Naoki
Christovam, Denise S.
Marino, Andrea
Takegami, Daiskue
Golskovskii, Andrei
Rosa, Priscila F. S.
Kuneš, Jan
Fujimori, Shin ichi
Tjeng, Liu Hao
Severing, Andrea
Hariki, Atsushi
author_facet Sundermann, Martin
Okauchi, Takaki
Ito, Naoki
Christovam, Denise S.
Marino, Andrea
Takegami, Daiskue
Golskovskii, Andrei
Rosa, Priscila F. S.
Kuneš, Jan
Fujimori, Shin ichi
Tjeng, Liu Hao
Severing, Andrea
Hariki, Atsushi
contents We investigate the nature of the 5$f$ electrons in the unconventional odd-parity superconductor UTe$_2$, focusing on the degree of covalency, localization versus itinerancy, and dominant electronic configuration. This is achieved using density functional theory (DFT) in combination with dynamical mean-field theory (DMFT) calculations. A key aspect of our approach is the material-specific tuning of the double-counting correction parameter, $μ_{\rm dc}$, within the DFT+DMFT part. This tuning is guided by the energy dependence of photo-ionization cross-sections in valence band photoelectron spectroscopy. The reliability of the parameters is confirmed by the accurate reproduction of the angle-resolved valence-band photoemission spectra and the U 4$f$ core-level data. The DFT+DMFT model reveals that in UTe$_2$ U 5$f^n$ configurations with n=1 to 4 contribute to the ground state, with the 5$f^2$ configuration being most prevalent and an average 5$f$ shell fillings close to 2.5. The model further suggests that the 5$f$ electrons form narrow bands and that charge fluctuations due to degeneracy play a role in addition to coherent valence dynamics arising from hybridization with the conduction bath. Additionally, the significance of the U 6$d$ states in UTe$_2$ is discussed.
format Preprint
id arxiv_https___arxiv_org_abs_2509_07915
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle UTe$_2$: a narrow band superconductor
Sundermann, Martin
Okauchi, Takaki
Ito, Naoki
Christovam, Denise S.
Marino, Andrea
Takegami, Daiskue
Golskovskii, Andrei
Rosa, Priscila F. S.
Kuneš, Jan
Fujimori, Shin ichi
Tjeng, Liu Hao
Severing, Andrea
Hariki, Atsushi
Strongly Correlated Electrons
Superconductivity
We investigate the nature of the 5$f$ electrons in the unconventional odd-parity superconductor UTe$_2$, focusing on the degree of covalency, localization versus itinerancy, and dominant electronic configuration. This is achieved using density functional theory (DFT) in combination with dynamical mean-field theory (DMFT) calculations. A key aspect of our approach is the material-specific tuning of the double-counting correction parameter, $μ_{\rm dc}$, within the DFT+DMFT part. This tuning is guided by the energy dependence of photo-ionization cross-sections in valence band photoelectron spectroscopy. The reliability of the parameters is confirmed by the accurate reproduction of the angle-resolved valence-band photoemission spectra and the U 4$f$ core-level data. The DFT+DMFT model reveals that in UTe$_2$ U 5$f^n$ configurations with n=1 to 4 contribute to the ground state, with the 5$f^2$ configuration being most prevalent and an average 5$f$ shell fillings close to 2.5. The model further suggests that the 5$f$ electrons form narrow bands and that charge fluctuations due to degeneracy play a role in addition to coherent valence dynamics arising from hybridization with the conduction bath. Additionally, the significance of the U 6$d$ states in UTe$_2$ is discussed.
title UTe$_2$: a narrow band superconductor
topic Strongly Correlated Electrons
Superconductivity
url https://arxiv.org/abs/2509.07915