TY  - JOUR
PB  - SciPost Foundation
DO  - 10.21468/SciPostPhys.15.1.008
TI  - Gapful electrons in a vortex core in granular superconductors
PY  - 2023/07/12
UR  - https://www.scipost.org/SciPostPhys.15.1.008
JF  - SciPost Physics
JA  - SciPost Phys.
VL  - 15
IS  - 1
SP  - 008
A1  - Kiselov, Dmitry
AU  - Skvortsov, Mikhail A.
AU  - Feigel'man, Mikhail V.
AB  - We calculate the quasiparticle density of states (DoS) inside the vortex core in a granular superconductor, generalizing the classical solution applicable for dirty superconductors. A discrete version of the Usadel equation for a vortex is derived and solved numerically for a broad range of parameters. Electron DoS is found to be gapful when the coherence length $\xi$ becomes comparable to the distance between neighboring grains $l$. Minigap magnitude $E_g$ grows from zero at $\xi \approx 1.4 l$ to third of superconducting gap $\Delta_0 $ at $\xi \approx 0.5 l$. The absence of low-energy excitations is the main ingredient needed to understand strong suppression of microwave dissipation recently observed in a mixed state of granular Al.
ER  -

@Article{10.21468/SciPostPhys.15.1.008,
	title={{Gapful electrons in a vortex core in granular superconductors}},
	author={Dmitry E. Kiselov and Mikhail A. Skvortsov and Mikhail V. Feigel'man},
	journal={SciPost Phys.},
	volume={15},
	pages={008},
	year={2023},
	publisher={SciPost},
	doi={10.21468/SciPostPhys.15.1.008},
	url={https://scipost.org/10.21468/SciPostPhys.15.1.008},
}