تقرير
Unconventional superconductivity in the strong-coupling limit for the heavy fermion system CeCoIn$_5$
| العنوان: | Unconventional superconductivity in the strong-coupling limit for the heavy fermion system CeCoIn$_5$ |
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| المؤلفون: | Fasano, Y., Szabó, P., Kačmarčík, J., Pribulová, Z., Pedrazzini, P., Samuely, P., Correa, V. F. |
| المصدر: | Physica B 536, 798 (2018) |
| سنة النشر: | 2017 |
| المجموعة: | Condensed Matter |
| مصطلحات موضوعية: | Condensed Matter - Superconductivity |
| الوصف: | We present scanning tunneling spectroscopy measurements of the local quasiparticles' excitation spectra of CeCoIn$_5$ between 440mK and 3K in samples with a bulk $T_{\rm c}=2.25$K. The spectral shape of our low-temperature tunneling data, quite textbook nodal-gap conductance, allow us to confidently fit the spectra with a d-wave density of states considering also a shortening of quasiparticles' lifetime term $\Gamma$. The $\Delta(0)$ value obtained from the fits yields a BCS ratio $2\Delta/kT_{\rm c} =7.73$ suggesting that CeCoIn$_5$ is an unconventional superconductor in the strong coupling limit. The fits also suggest that the height of coherence peaks in CeCoIn$_5$ is reduced with respect to a pure BCS spectra and therefore the coupling of quasiparticles with spin excitations should play a relevant role. In addition, the tunneling conductance shows a depletion at energies smaller than $\Delta$ for temperatures larger than the bulk $T_{\rm c}$, giving further support to the existence of a pseudogap phase that in our samples span up to $T^{*}\sim 1.2 T_{\rm c}$. The phenomenological scaling of the pseudogap temperature observed in various families of cuprates, $2\Delta/kT^{*} \sim 4.3 $, is not fulfilled in our measurements. This suggests that in CeCoIn$_5$ the strong magnetic fluctuations might conspire to close the local superconducting gap at a smaller pesudogap temperature-scale than in cuprates. Comment: 4 figures, Proceedings to the SCES conference 2017 |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.1016/j.physb.2017.10.034 |
| URL الوصول: | http://arxiv.org/abs/1710.04546 |
| رقم الأكسشن: | edsarx.1710.04546 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.1016/j.physb.2017.10.034 |
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