Giant Splitting of Folded Dirac Bands in Kekulé-ordered Graphene with Eu Intercalation

Fuente: arXiv
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Main Authors: Qiu, Xiaodong, Zhu, Tongshuai, Fan, Zhenjie, Wang, Kaili, Mu, Yuyang, Yang, Bin, Wu, Di, Zhang, Haijun, Wang, Can, Wang, Huaiqiang, Zhang, Yi
Format: Preprint
Published: 2025
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author Qiu, Xiaodong
Zhu, Tongshuai
Fan, Zhenjie
Wang, Kaili
Mu, Yuyang
Yang, Bin
Wu, Di
Zhang, Haijun
Wang, Can
Wang, Huaiqiang
Zhang, Yi
author_facet Qiu, Xiaodong
Zhu, Tongshuai
Fan, Zhenjie
Wang, Kaili
Mu, Yuyang
Yang, Bin
Wu, Di
Zhang, Haijun
Wang, Can
Wang, Huaiqiang
Zhang, Yi
contents Kekulé-ordered graphene on SiC realized by intercalating two-dimensional metal layers offers a versatile platform for exploring intriguing quantum states and phenomena. Here, we achieve the intercalation of $(\mathrm{\sqrt{3}\times\sqrt{3}})\mathit{R}30^\circ$-ordered Eu layer between epitaxial graphene and SiC substrate, realizing a Kekulé graphene with large local magnetic moments of intercalated Eu atoms. Combining angle-resolved photoemission spectroscopy (ARPES) and density functional theory (DFT) calculations, we revealed that the Kekul{é} order folds the Dirac cones of graphene from the corners to the Brillouin zone center via intervalley scattering, forming the replica Dirac bands with gap opening. More intriguingly, the Dirac fermions in the replica Dirac bands show a strong exchange coupling with the localized magnetic moments of Eu $4f$ orbitals, resulting in a giant splitting of the folded Dirac bands. The observation of strong coupling between Dirac fermions and local magnetic moments of Eu $4f$ electrons via Kekulé order pave a new way for generating Dirac band splitting in graphene, advancing the potential applications of Kekulé-ordered graphene in spintronics, as well as exploring intriguing physical properties and correlation states for quantum technology.
format Preprint
id arxiv_https___arxiv_org_abs_2509_05633
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Giant Splitting of Folded Dirac Bands in Kekulé-ordered Graphene with Eu Intercalation
Qiu, Xiaodong
Zhu, Tongshuai
Fan, Zhenjie
Wang, Kaili
Mu, Yuyang
Yang, Bin
Wu, Di
Zhang, Haijun
Wang, Can
Wang, Huaiqiang
Zhang, Yi
Strongly Correlated Electrons
Mesoscale and Nanoscale Physics
Materials Science
Kekulé-ordered graphene on SiC realized by intercalating two-dimensional metal layers offers a versatile platform for exploring intriguing quantum states and phenomena. Here, we achieve the intercalation of $(\mathrm{\sqrt{3}\times\sqrt{3}})\mathit{R}30^\circ$-ordered Eu layer between epitaxial graphene and SiC substrate, realizing a Kekulé graphene with large local magnetic moments of intercalated Eu atoms. Combining angle-resolved photoemission spectroscopy (ARPES) and density functional theory (DFT) calculations, we revealed that the Kekul{é} order folds the Dirac cones of graphene from the corners to the Brillouin zone center via intervalley scattering, forming the replica Dirac bands with gap opening. More intriguingly, the Dirac fermions in the replica Dirac bands show a strong exchange coupling with the localized magnetic moments of Eu $4f$ orbitals, resulting in a giant splitting of the folded Dirac bands. The observation of strong coupling between Dirac fermions and local magnetic moments of Eu $4f$ electrons via Kekulé order pave a new way for generating Dirac band splitting in graphene, advancing the potential applications of Kekulé-ordered graphene in spintronics, as well as exploring intriguing physical properties and correlation states for quantum technology.
title Giant Splitting of Folded Dirac Bands in Kekulé-ordered Graphene with Eu Intercalation
topic Strongly Correlated Electrons
Mesoscale and Nanoscale Physics
Materials Science
url https://arxiv.org/abs/2509.05633