Effects of intercomponent couplings on the appearance of time-reversal symmetry breaking fermion-quadrupling states in two-component London models

Abstract

Detection of a bosonic metallic state that breaks the ${Z}_{2}$ time-reversal symmetry has been recently reported in ${\mathrm{Ba}}_{1\ensuremath{-}x}{\mathrm{K}}_{x}{\mathrm{Fe}}_{2}{\mathrm{As}}_{2}$ with a doping level $x\ensuremath{\approx}0.8$. This is a metallic state of fermionic quadruplets that breaks time-reversal symmetry. As such, it has no condensed Cooper pairs but has a long-range order between fermionic quartets. In the present paper, we investigate the emergence of this phase in a two-component London model via Monte Carlo simulations as a function of various intercomponent couplings.

Topics & Concepts