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| Main Authors: | , , , , , , , , , , , |
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| Format: | Preprint |
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2026
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2605.24536 |
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| _version_ | 1866918519899160576 |
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| author | Aarti Samanta, Dibyendu Panda, Kartik Adroja, Devashibhai Ram, Daloo Hossain, Zakir Stewart, Rhea Hillier, Adrian Bhattacharyya, Amitava Layek, Samar Ghosh, Sudeep Kumar Anand, Vivek Kumar |
| author_facet | Aarti Samanta, Dibyendu Panda, Kartik Adroja, Devashibhai Ram, Daloo Hossain, Zakir Stewart, Rhea Hillier, Adrian Bhattacharyya, Amitava Layek, Samar Ghosh, Sudeep Kumar Anand, Vivek Kumar |
| contents | In Z2 topological metals, nontrivial band topology and strong spin-orbit coupling (SOC) impose symmetry constraints that can stabilize unconventional superconducting states, even when thermodynamic probes indicate an isotropic gap. Here, we investigate the superconducting ground state of such a material, SrPd2As2, using muon spin rotation and relaxation (muSR), first-principles calculations, and Ginzburg-Landau analysis. Transverse-field muSR indicates a fully gapped superconducting state below Tc = 0.94 K, while zero-field muSR detects spontaneous internal magnetic fields below Tc, establishing time-reversal symmetry (TRS) breaking. Electronic structure calculations identify SrPd2As2 as a Z2 topological metal with surface states crossing the Fermi level. Standard anisotropic Migdal-Eliashberg calculations predict a nodal gap and overestimate Tc, indicating that a purely phonon-mediated pairing mechanism is insufficient. We resolve this apparent contradiction by showing that the interplay of SOC, tetragonal symmetry, and an open Fermi surface topology stabilizes a nonunitary triplet superconducting state whose symmetry-imposed nodes lie in momentum-space regions devoid of electronic states. This yields a fully gapped thermodynamic response while naturally breaking TRS. Our results establish SrPd2As2 as a clean platform for bulk nonunitary triplet pairing and a promising candidate for intrinsic topological superconductivity. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2605_24536 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Nonunitary triplet superconductivity in the Z2 topological metal SrPd2As2 Aarti Samanta, Dibyendu Panda, Kartik Adroja, Devashibhai Ram, Daloo Hossain, Zakir Stewart, Rhea Hillier, Adrian Bhattacharyya, Amitava Layek, Samar Ghosh, Sudeep Kumar Anand, Vivek Kumar Superconductivity Materials Science Strongly Correlated Electrons In Z2 topological metals, nontrivial band topology and strong spin-orbit coupling (SOC) impose symmetry constraints that can stabilize unconventional superconducting states, even when thermodynamic probes indicate an isotropic gap. Here, we investigate the superconducting ground state of such a material, SrPd2As2, using muon spin rotation and relaxation (muSR), first-principles calculations, and Ginzburg-Landau analysis. Transverse-field muSR indicates a fully gapped superconducting state below Tc = 0.94 K, while zero-field muSR detects spontaneous internal magnetic fields below Tc, establishing time-reversal symmetry (TRS) breaking. Electronic structure calculations identify SrPd2As2 as a Z2 topological metal with surface states crossing the Fermi level. Standard anisotropic Migdal-Eliashberg calculations predict a nodal gap and overestimate Tc, indicating that a purely phonon-mediated pairing mechanism is insufficient. We resolve this apparent contradiction by showing that the interplay of SOC, tetragonal symmetry, and an open Fermi surface topology stabilizes a nonunitary triplet superconducting state whose symmetry-imposed nodes lie in momentum-space regions devoid of electronic states. This yields a fully gapped thermodynamic response while naturally breaking TRS. Our results establish SrPd2As2 as a clean platform for bulk nonunitary triplet pairing and a promising candidate for intrinsic topological superconductivity. |
| title | Nonunitary triplet superconductivity in the Z2 topological metal SrPd2As2 |
| topic | Superconductivity Materials Science Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2605.24536 |