Configuration-dependent edge and corner superconductivity in 𝑠-wave kagome superconductors

Chinese Journal of Physics. 2026. Vol. 103. P. 1803–1814.

Huang D., Chen Y., Luo X., Zhu Q., Shanenko A.

Using self-consistent Bogoliubov-de Gennes calculations for kagome flakes framed by armchair
and flat edges, we observe a configuration-dependent spatial inhomogeneity of an 𝑠-wave superconducting
condensate. Specifically, at half-filling, the local pair potential is significantly enhanced
by up to 77.8% at edge centers and up to 148.9% at corners, subsequently boosting their
local critical temperatures by up to 13.5% and 74.2%, respectively, relative to the bulk (flake center).
We also find that, microscopically, the edge enhancement of the critical temperature arises
from the constructive superposition of extended quasiparticle states. The origin of corner superconductivity,
however, is twofold and geometry-dependent. Corner enhancements can arise from
the quasiparticle interference, but they can also be driven by geometry-confined corner quasiparticles,
which yield the most pronounced increase in the local critical temperature. By revealing
these two mechanisms underlying the boundary (edge and corner) enhancements of superconductivity
in the kagome flakes, our study encourages further exploration of superconducting systems
with nontrivial atomic structures as promising candidates for realizing systems with a nonuniform
critical temperature that varies spatially within the same sample.

Keywords: kagome lattice, Edge superconductivity, Краевая сверхпроводимость, кагоме решётка

Publication based on the results of: Влияние конкурирующих взаимодействий и топологии на критические параметры современных сверхпроводящих материалов (2027)