Multiband superconductivity in the topological Kramers nodal-line semimetals

Fuente: arXiv
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Main Authors: Shang, Tian, Zhao, Jianzhou, Xia, Keqi, Hu, Lun-Hui, Xu, Yang, Zhan, Qingfeng, Gawryluk, Dariusz Jakub, Shiroka, Toni
Format: Preprint
Published: 2025
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author Shang, Tian
Zhao, Jianzhou
Xia, Keqi
Hu, Lun-Hui
Xu, Yang
Zhan, Qingfeng
Gawryluk, Dariusz Jakub
Shiroka, Toni
author_facet Shang, Tian
Zhao, Jianzhou
Xia, Keqi
Hu, Lun-Hui
Xu, Yang
Zhan, Qingfeng
Gawryluk, Dariusz Jakub
Shiroka, Toni
contents Recent band-structure calculations predict that the ruthenium-based ternary silicides are three-dimensional Kramers nodal line semimetals. Among them, NbRuSi and TaRuSi show bulk superconductivity (SC) below $T_c \sim 3$ K and 4 K, as well as spontaneous magnetic fields. The latter indicates the breaking of time-reversal symmetry and, thus, unconventional SC in both compounds. Previous temperature-dependent muon-spin spectroscopy studies failed to distinguish whether such compounds exhibit single-gap or multi-gap SC. Here, we report on systematic measurements of the field-dependent muon-spin relaxation rates in the superconducting state and on temperature-dependent electrical resistivity and specific heat under applied magnetic fields. Both the upper critical field and the field-dependent superconducting relaxation are well described by a two-band model. By combining our experimental results with numerical band-structure calculations, we provide solid evidence for multiband SC in NbRuSi and TaRuSi, and thus offer further insight into the unconventional- and topological nature of their superconductivity.
format Preprint
id arxiv_https___arxiv_org_abs_2506_03509
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Multiband superconductivity in the topological Kramers nodal-line semimetals
Shang, Tian
Zhao, Jianzhou
Xia, Keqi
Hu, Lun-Hui
Xu, Yang
Zhan, Qingfeng
Gawryluk, Dariusz Jakub
Shiroka, Toni
Superconductivity
Strongly Correlated Electrons
Recent band-structure calculations predict that the ruthenium-based ternary silicides are three-dimensional Kramers nodal line semimetals. Among them, NbRuSi and TaRuSi show bulk superconductivity (SC) below $T_c \sim 3$ K and 4 K, as well as spontaneous magnetic fields. The latter indicates the breaking of time-reversal symmetry and, thus, unconventional SC in both compounds. Previous temperature-dependent muon-spin spectroscopy studies failed to distinguish whether such compounds exhibit single-gap or multi-gap SC. Here, we report on systematic measurements of the field-dependent muon-spin relaxation rates in the superconducting state and on temperature-dependent electrical resistivity and specific heat under applied magnetic fields. Both the upper critical field and the field-dependent superconducting relaxation are well described by a two-band model. By combining our experimental results with numerical band-structure calculations, we provide solid evidence for multiband SC in NbRuSi and TaRuSi, and thus offer further insight into the unconventional- and topological nature of their superconductivity.
title Multiband superconductivity in the topological Kramers nodal-line semimetals
topic Superconductivity
Strongly Correlated Electrons
url https://arxiv.org/abs/2506.03509