Speaker
Description
Motivated by experimental developments reporting evidence of time-reversal symmetry breaking in the superconducting state of kagome metals, an investigation into the nature of vortices in chiral $d+id$ superconductors on the kagome lattice will be presented. Using self-consistent microscopic calculations that incorporate the band structure characteristics of the kagome lattice, the ground-state condensate in the presence of an external field was found to host fractional vortices. Each fractional vortex carries one-third of the superconducting flux quantum and exhibits a characteristic signature related to one of the three sublattice degrees of freedom of the kagome lattice. Extending these calculations to the altermagnetic bipartite square lattice, the vortex state of the four-fold degenerate chiral equal-spin pairing $p+ip$-wave state is explored. With the decoupling of the two spin condensates in addition to the chiral order of the individual condensates, this system offers a wide range of possibilities for the realization of fractional vortex states.