Fig. 5: Non-reciprocal phase transitions in light-activated layered ferromagnets.
a Layered ferromagnet composed of A and B layers separated by a non-magnetic metal exposed of light injection that activates the B layer. The interlayer RKKY interaction is mediated by the itinerant electrons in the non-magnetic metal layer, which is modified by light. In particular, the magnetization in the A layer aligns with the rate αAjAB for ferromagnetic interlayer interactions jAB > 0, while the B layer may align or antialign with layer A depending on the sign of the modified effective interaction αBjAB − ΩAB. φA(B) is the orientation direction of the magnetization mA(B) of A(B)-layer ferromagnet. b–d Different phases arising in this system. b Aligned phase (Δφ = φA − φB = 0) realized in the equilibrium limit γB = 0. c Antialigned phase (Δφ = π) at γB/(αB∣gB∣) = 1.1. d Chiral phase (Δφ ≠0, π) at γB/(αB∣gB∣) = 1.5. (e) The orientation angle difference Δφ and (f) the magnitude of the magnetization ∣mA,B∣ as a function of γB. We set jAB = 5 meV, kBT = 9 meV, and the other parameters are the same as those used in Fig. 1c). The simulations were run from random initial conditions and have been checked that there is essentially no initial condition dependence on the final state.
