Doped Kagome System as Exotic Superconductor

TL;DR

This paper models a doped kagome system as an exotic superconductor with unique flux vortices and fractional quasiparticles, revealing novel topological and symmetry-breaking properties.

Contribution

It introduces a Chern--Simons theoretical framework for the doped kagome system, demonstrating its exotic superconducting state with fractional flux vortices and quasiparticles.

Findings

System is an exotic superconductor breaking time-reversal symmetry.

Contains minimal vortices of flux hc/4e, unlike conventional hc/2e.

Hosts fractional quasiparticles with semionic and bosonic statistics.

Abstract

A Chern--Simons theory for the doped spin-1/2 kagom\'e system is constructed, from which it is shown that the system is an exotic superconductor that breaks time-reversal symmetry. It is also shown that the system carries minimal vortices of flux $hc/4e$ (as opposed to the usual $hc/2e$ in conventional superconductors) and contains fractional quasiparticles (including fermionic quasiparticles with \emph{semionic} mutual statistics and spin-1/2 quasiparticles with \emph{bosonic} self-statistics) in addition to the usual spin-1/2 fermionic Bougoliubov quasiparticle. Two Chern--Simons theories--one with an auxiliary gauge field kept and one with the auxiliary field and a redundant matter field directly eliminated--are presented and shown to be consistent with each other.