Correlated charge order intertwined with time-reversal symmetry-breaking nodal superconductivity in the dual flat band kagome superconductor CeRu$_{3}$Si$_{2}$

Fuente: arXiv
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Main Authors: Gerguri, O., Kràl, P., Spitaler, M., Salamin, M., Graham, J. N., Doll, A., Biało, I., Plokhikh, I., Krieger, J., Hicken, T. J., Oppliger, J., Martinelli, L., Steppke, A., Shepelin, N., Khasanov, R., Zimmermann, M. v., Monserrat, B., Luetkens, H., Chang, J., von Rohr, F. O., Kim, Sun-Woo, Guguchia, Z.
Format: Preprint
Published: 2026
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author Gerguri, O.
Kràl, P.
Spitaler, M.
Salamin, M.
Graham, J. N.
Doll, A.
Biało, I.
Plokhikh, I.
Krieger, J.
Hicken, T. J.
Oppliger, J.
Martinelli, L.
Steppke, A.
Shepelin, N.
Khasanov, R.
Zimmermann, M. v.
Monserrat, B.
Luetkens, H.
Chang, J.
von Rohr, F. O.
Kim, Sun-Woo
Guguchia, Z.
author_facet Gerguri, O.
Kràl, P.
Spitaler, M.
Salamin, M.
Graham, J. N.
Doll, A.
Biało, I.
Plokhikh, I.
Krieger, J.
Hicken, T. J.
Oppliger, J.
Martinelli, L.
Steppke, A.
Shepelin, N.
Khasanov, R.
Zimmermann, M. v.
Monserrat, B.
Luetkens, H.
Chang, J.
von Rohr, F. O.
Kim, Sun-Woo
Guguchia, Z.
contents Kagome materials provide a powerful platform for exploring how flat electronic bands promote symmetry-breaking quantum states, yet studies have so far focused mainly on kagome-derived $d$-electron flat bands. In this paper, we introduce CeRu$_{3}$Si$_{2}$, a kagome superconductor in which our first-principles calculations show the coexistence of Ru $d$-orbital kagome flat bands and heavy-fermion flat bands derived from Ce$^{4+}$ $4f$-states. X-ray diffraction reveals a dominant 1/2 charge order with a much weaker 1/3 component persisting up to room temperature. Theoretical calculations further highlight the correlated nature of these charge-order states. Deep within the charge-ordered state, magnetoresistance emerges below 80 K and strengthens further below 30 K. Zero-field muon spin-rotation measurements show no time-reversal symmetry (TRS) breaking in the normal state, in contrast to LaRu$_{3}$Si$_{2}$ and YRu$_{3}$Si$_{2}$. However, an applied magnetic field induces weak magnetism. Across the $A$Ru$_{3}$Si$_{2}$ family ($A$ = La, Y, and Ce), the superconducting transition temperature $T_{\rm c}$ scales linearly with the onset temperature of normal-state TRS breaking $T_{\rm {TRSB}}$ and the magnitude of the field-induced magnetic response, revealing a direct positive correlation between normal-state symmetry breaking and superconductivity. Furthermore, we identify that CeRu$_{3}$Si$_{2}$ is the first 132-type kagome compound to host nodal superconductivity together with spontaneous internal magnetic fields, providing clear evidence for intrinsic TRS breaking in the superconducting state. These results establish CeRu$_{3}$Si$_{2}$ as a unique platform where intertwined kagome $d$- and heavy fermion $f$-electron flat bands generate a rich hierarchy of electronic orders.
format Preprint
id arxiv_https___arxiv_org_abs_2603_27408
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Correlated charge order intertwined with time-reversal symmetry-breaking nodal superconductivity in the dual flat band kagome superconductor CeRu$_{3}$Si$_{2}$
Gerguri, O.
Kràl, P.
Spitaler, M.
Salamin, M.
Graham, J. N.
Doll, A.
Biało, I.
Plokhikh, I.
Krieger, J.
Hicken, T. J.
Oppliger, J.
Martinelli, L.
Steppke, A.
Shepelin, N.
Khasanov, R.
Zimmermann, M. v.
Monserrat, B.
Luetkens, H.
Chang, J.
von Rohr, F. O.
Kim, Sun-Woo
Guguchia, Z.
Superconductivity
Materials Science
Strongly Correlated Electrons
Kagome materials provide a powerful platform for exploring how flat electronic bands promote symmetry-breaking quantum states, yet studies have so far focused mainly on kagome-derived $d$-electron flat bands. In this paper, we introduce CeRu$_{3}$Si$_{2}$, a kagome superconductor in which our first-principles calculations show the coexistence of Ru $d$-orbital kagome flat bands and heavy-fermion flat bands derived from Ce$^{4+}$ $4f$-states. X-ray diffraction reveals a dominant 1/2 charge order with a much weaker 1/3 component persisting up to room temperature. Theoretical calculations further highlight the correlated nature of these charge-order states. Deep within the charge-ordered state, magnetoresistance emerges below 80 K and strengthens further below 30 K. Zero-field muon spin-rotation measurements show no time-reversal symmetry (TRS) breaking in the normal state, in contrast to LaRu$_{3}$Si$_{2}$ and YRu$_{3}$Si$_{2}$. However, an applied magnetic field induces weak magnetism. Across the $A$Ru$_{3}$Si$_{2}$ family ($A$ = La, Y, and Ce), the superconducting transition temperature $T_{\rm c}$ scales linearly with the onset temperature of normal-state TRS breaking $T_{\rm {TRSB}}$ and the magnitude of the field-induced magnetic response, revealing a direct positive correlation between normal-state symmetry breaking and superconductivity. Furthermore, we identify that CeRu$_{3}$Si$_{2}$ is the first 132-type kagome compound to host nodal superconductivity together with spontaneous internal magnetic fields, providing clear evidence for intrinsic TRS breaking in the superconducting state. These results establish CeRu$_{3}$Si$_{2}$ as a unique platform where intertwined kagome $d$- and heavy fermion $f$-electron flat bands generate a rich hierarchy of electronic orders.
title Correlated charge order intertwined with time-reversal symmetry-breaking nodal superconductivity in the dual flat band kagome superconductor CeRu$_{3}$Si$_{2}$
topic Superconductivity
Materials Science
Strongly Correlated Electrons
url https://arxiv.org/abs/2603.27408