Quasiclassical theory of C₄-symmetric magnetic order in disordered iron-based superconductors

In some hole-doped iron-based superconductors the magnetic order emerges with underlying C₄-symmetry. This magnetic order can be viewed as a state with two ordering vectors with the corresponding magnetizations M₁ and M₂. In my talk, I will formulate a quasi-classical theory of such a state. Specifically, I will consider a three-band model, which, apart from the magnetic interactions, includes intra- and interband disorder scattering potentials. I will develop the quasiclassical approach for such a model and show how disorder scattering rates enhance the emergence of the C₄-symmetric magnetic order.