Moiré Skyrmions in Twisted CrX3 (X = I, Br, and Cl) Bilayers: Part (II) Atomistic Simulations

We present a comprehensive theory of the magnetic phases in twisted bilayer chromium trihalides through first-principles calculations and atomistic simulations [1]. In this talk, the atomistic simulations will be described. In order to find the ground state for the bilayer Hamiltonian, we introduce the Dzyaloshinskii−Moriya interaction  (DMI) and solve the Landau-Lifshitz-Gilbert equations. As a result of the competing interlayer antiferromagnetic coupling and the energy cost for forming ferromagnetic-antiferromagnetic domain walls, a wide range of noncollinear magnetic phases can be stabilized as a function of the twist angle and DMI. In particular, for small twist angles, various skyrmion crystal phases can be stabilized in both CrI₃ and CrBr₃. Our results provide an interpretation for the recent observation of noncollinear magnetic phases in twisted bilayer CrI₃ and demonstrate the possibility of engineering further nontrivial magnetic ground states in twisted bilayer chromium trihalides.