Weng, Z.F., Zhang, J.L., Smidman, M., Shang, T., Quintanilla, J., Annett, J.F., Nicklas, M., Pang, G.M., Jiao, L., Jiang, W.B., and others. (2016) Two-gap superconductivity in LaNiGa\(_2\) with nonunitary triplet pairing and even parity gap symmetry. Physical Review Letters, 117 (2). Article Number 027001. ISSN 0031-9007. E-ISSN 1079-7114. (doi:10.1103/PhysRevLett.117.027001) (KAR id:55951)
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Official URL: http://dx.doi.org/10.1103/PhysRevLett.117.027001 |
Abstract
The nature of the pairing states of superconducting LaNiC\(_2\) and LaNiGa\(_2\) has to date remained a puzzling question. Broken time reversal symmetry has been observed in both compounds and a group theoretical analysis implies a non-unitary triplet pairing state. However all the allowed non-unitary triplet states have nodal gap functions but most thermodynamic and NMR measurements indicate fully gapped superconductivity in LaNiC\(_2\). Here we probe the gap symmetry of LaNiGa\(_2\) by measuring the London penetration depth, specific heat and upper critical field. These measurements demonstrate two-gap nodeless superconductivity in LaNiGa\(_2\), suggesting that this is a common feature of both compounds. These results allow us to propose a novel triplet superconducting state, where the pairing occurs between electrons of the same spin, but on different orbitals. In this case the superconducting wavefunction has a triplet spin component but isotropic even parity gap symmetry, yet the overall wavefunction remains antisymmetric under particle exchange. This model leads to a nodeless two-gap superconducting state which breaks time reversal symmetry, and therefore accounts well for the seemingly contradictory experimental results.
Item Type: | Article |
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DOI/Identification number: | 10.1103/PhysRevLett.117.027001 |
Uncontrolled keywords: | Physics of Quantum Materials, LaNiGa2, superconductivity, centrosymmetric, broken time-reversal symmetry, gap, BCS theory, LaNiC2 |
Subjects: |
Q Science > QC Physics > QC173.45 Condensed Matter Q Science > QC Physics > QC176 Solid state physics |
Divisions: | Divisions > Division of Natural Sciences > Physics and Astronomy |
Funders: |
Organisations -1 not found. Organisations -1 not found. Organisations -1 not found. Organisations -1 not found. |
Depositing User: | Jorge Quintanilla Tizon |
Date Deposited: | 15 Jun 2016 10:33 UTC |
Last Modified: | 04 Jul 2023 14:01 UTC |
Resource URI: | https://kar.kent.ac.uk/id/eprint/55951 (The current URI for this page, for reference purposes) |
Quintanilla, J.: |
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