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Abstract
A recent Little-Parks experiment on kagome superconductor CsV3Sb5 has revealed remarkable resistance oscillations with period ϕ0/3=hc/6e [1]. In this talk, I will present a theoretical analysis based on the Ginzburg-Landau free energy functional, which incorporates repulsive Josephson-type couplings among three pair-density wave (PDW) orders [2]. These coupling results in the time-reversal symmetry breaking in the ground state.
For a ring geometry, we found a series of intermediate states where the phase of one SC order parameter winds 2p more or less than the other two around the ring. These configurations result in local free-energy minima at integer multiples of ϕ0/3. We show that the ground-state degeneracy associated with a Z2 chirality is crucial. Furthermore, the Higgs-Leggett mechanism stabilizes domain walls between chiral domains. At low temperatures domain walls are expelled from the system resulting in free-energy minima only at integer multiples of ϕ0.
Our theory offers a compelling explanation for the observed 6e SC signals in the Little-Parks experiment on kagome superconductors.
[1] L.-F. Zhang, Z. Wang, and X. Hu, Commun Phys 7, 210 (2024).
[2] J. Ge, et al., Phys. Rev. X 14, 021025 (2024).
Biography
Ling-Feng Zhang obtained his PhD from the University of Antwerp, Belgium, in 2015. Following his doctorate, he conducted postdoctoral research at the same institution and was awarded an FWO Postdoctoral Fellowship in Belgium. In 2021, He joined Shanghai University. His research interests lie in condensed matter theory and numerical simulations, with a focus on mesoscopic and microscopic superconductors, vortex matter, and unconventional superconductors. He published over 20 papers including PRL, Advanced materials and Communications Physics.
Division
Condensed Matter
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