Abstract
AbstractA recent Little-Parks experiment in Kagome-structured superconductor CsV3Sb5 demonstrated resistance oscillations with period $${\phi }_{0}/3={hc}/6e$$
ϕ
0
/
3
=
h
c
/
6
e
. Here, we perform analysis based on a theory involving three $$2{{{{{\rm{e}}}}}}$$
2
e
superconductivity (SC) order parameters associated with the three reciprocal lattice vectors which connect M points of the hexagonal Brillouin zone. In a ring geometry we find that, as a series of intermediate states, phase of one SC order parameter winds 2π more or less than the other two ones around the ring, which yields local free-energy minima at integer multiples of $${\phi }_{0}/3$$
ϕ
0
/
3
. It is unveiled that the ground-state degeneracy associated with a Z2 chirality is crucial, and the Higgs-Leggett mechanism stabilizes domain walls (DWs) between chiral domains. At low temperatures DWs are expelled from the system resulting in free-energy minima only at integer multiples of $${\phi }_{0}$$
ϕ
0
. Our theory explains successfully the fractional quantization of magnetic flux $${\phi }_{0}/3$$
ϕ
0
/
3
observed in experiments, which opens a door for approaching rich physics of Kagome superconductors.
Funder
CREST, JST (Core Research for Evolutionary Science and Technology, Japan Science and Technology Agency)
Publisher
Springer Science and Business Media LLC
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