This non-collinear magnetic state, the so-called 2Q state, is the superposition of two spin-spiral states with perpendicular spiral vector q on a square lattice. It can be stabilized by higher order interactions beyond the Heisenberg model, such as the biquadratic or the four-spin interactions, in case they are comparable with the exchange coupling. (Phys. Rev. Lett. 99, 187203 (2007)).