Pairing symmetry in infinite-layer nickelate superconductor
| Autor: | Chow, L. E., Sudheesh, S. Kunniniyil, Luo, Z. Y., Nandi, P., Heil, T., Deuschle, J., Zeng, S. W., Zhang, Z. T., Prakash, S., Du, X. M., Lim, Z. S., van Aken, Peter A., Chia, Elbert E. M., Ariando, A. |
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| Rok vydání: | 2022 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| Popis: | The superconducting infinite-layer nickelate family has risen as a promising platform for revealing the mechanism of high-temperature superconductivity. However, its challenging material synthesis has obscured effort in understanding the nature of its ground state and low-lying excitations, which is a prerequisite for identifying the origin of the Cooper pairing in high-temperature superconductors. In particular, the superconducting gap symmetry of nickelates has hardly been investigated and remains controversial. Here, we report the pairing symmetry of the infinite-layer nickelates determined by London penetration depth measurements in neodymium-based (Nd,Sr)NiO$_2$ and lanthanide-based (La,Ca)NiO$_2$ thin films of high crystallinity. A rare-earth-specific order parameter is observed. While the lanthanide nickelates follow dirty line-node behaviour, the neodymium-counterpart exhibits nodeless order parameters such as the $(d+is)$ wave. In contrast to the cuprates, our results suggest that the superconducting order parameter in nickelates is beyond a single $d_(x^2-y^2 )$-wave gap. Furthermore, the superfluid density shows a long tail near the superconducting transition temperature which is consistent with the emergence of a two-dimensional to three-dimensional crossover in the superconducting state. These observations challenge the early theoretical framework and propel further experimental and theoretical interests in the pairing nature of the infinite-layer nickelate family. Comment: Main manuscript: 26 pages, 3 figures; Supplementary file: 11 pages, 3 figures |
| Databáze: | arXiv |
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