Tuning London penetreation depth anisotropy with Disorder in the CaKFe<sub>4</sub>As<sub>4</sub> Superconductor
ORAL
Abstract
We report on the anisotropic behavior of the London penetration depth of CaK(Fe1−xNix)4As4 (CaK1144), discussing how it relates to its electronic structure and how it can be tuned by disorder to match specific requirements for applications.
The London penetration depth was measured with a microwave technique [1] that allowed us to deconvolve its anisotropic contributions and obtain the anisotropy parameter γλ [2]. Single crystals with Ni doping level x=0, 0.017, and 0.034 were analyzed both in the pristine state and after 3.5 MeV proton irradiation to introduce scattering centers.
The data found are in good agreement with previous literature [3] and are here compared to ab-initio density functional theory and Eliashberg calculations, showing that gap anisotropy in CaK1144 is present.
The dependence of γλ on both chemical and irradiation-induced disorder is discussed to highlight which methods are more suitable to optimize the material, in light of the recent employment of CaK1144 in the production of wires [4].
References
[1] G. Ghigo et al., Phys. Rev. B 96 (2017) 014501
[2] D. Torsello et al., Phys. Rev. B 100 (2019) 094513
[3] R. Khasanov et al., Phys. Rev. B 99 (2019) 140507
[4] S. Pyon et al., Appl. Phys. Express 11 (2018) 123101
The London penetration depth was measured with a microwave technique [1] that allowed us to deconvolve its anisotropic contributions and obtain the anisotropy parameter γλ [2]. Single crystals with Ni doping level x=0, 0.017, and 0.034 were analyzed both in the pristine state and after 3.5 MeV proton irradiation to introduce scattering centers.
The data found are in good agreement with previous literature [3] and are here compared to ab-initio density functional theory and Eliashberg calculations, showing that gap anisotropy in CaK1144 is present.
The dependence of γλ on both chemical and irradiation-induced disorder is discussed to highlight which methods are more suitable to optimize the material, in light of the recent employment of CaK1144 in the production of wires [4].
References
[1] G. Ghigo et al., Phys. Rev. B 96 (2017) 014501
[2] D. Torsello et al., Phys. Rev. B 100 (2019) 094513
[3] R. Khasanov et al., Phys. Rev. B 99 (2019) 140507
[4] S. Pyon et al., Appl. Phys. Express 11 (2018) 123101
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Presenters
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Daniele Torsello
- Department of Applied Science and Technology, Politecnico di Torino