Arguments were recently advanced that hole-doped Ba1βxβKxβFe2βAs2β
exhibits s+is state at certain doping. Spontaneous breaking of time reversal
symmetry in s+is state, dictates that it possess domain wall excitations.
Here, we discuss what are the experimentally detectable signatures of domain
walls in s+is state. We find that in this state the domain walls can have
dipole-like magnetic signature (in contrast to the uniform magnetic signature
of domain walls p+ip superconductors). We propose experiments where
quench-induced domain walls can be stabilized by geometric barriers and be
observed via their magnetic signature or their influence on the magnetization
process, thereby providing an experimental tool to confirm s+is state.Comment: Replaced with a version in print in Physical Review Letters; Minor
changes; 8 pages, 9 figure