| Autor: |
Hayes, Ian M., Metz, Tristin E., Frank, Corey E., Saha, Shanta R., Butch, Nicholas P., Mishra, Vivek, Hirschfeld, Peter J., Paglione, Johnpierre |
| Rok vydání: |
2024 |
| Předmět: |
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| Druh dokumentu: |
Working Paper |
| Popis: |
The superconducting state of the heavy-fermion metal UTe$_2$ has attracted considerable interest because of evidence for spin-triplet Cooper pairing and non-trivial topology. Progress on these questions requires identifying the presence or absence of nodes in the superconducting gap function and their dimension. In this article we report a comprehensive study of the influence of disorder on the thermal transport in the superconducting state of UTe$_2$. Through detailed measurements of the magnetic field dependence of the thermal conductivity in the zero-temperature limit, we obtain clear evidence for the presence of point nodes in the superconducting gap for all samples with transition temperatures ranging from 1.6~K to 2.1~K obtained by different synthesis methods, including a refined self-flux method. This robustness implies the presence of symmetry-imposed nodes throughout the range studied, further confirmed via disorder-dependent calculations of the thermal transport in a model with a single pair of nodes. In addition to capturing the temperature dependence of the thermal conductivity up to $T_c$, this model allows us to limit the possible locations of the nodes, suggesting a B$_{1u}$ or B$_{2u}$ symmetry for the superconducting order parameter. Additionally, comparing the new, ultra-high conductivity samples to older samples reveals a crossover between a low-field and a high field regime at a single value of the magnetic field in all samples. In the high field regime, the thermal conductivity at different disorder levels differ from each other by a simple offset, suggesting that some simple principle determines the physics of the mixed state, a fact which may illuminate trends observed in other clean nodal superconductors. |
| Databáze: |
arXiv |
| Externí odkaz: |
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