The discovery of atomically thin van der Waals magnetic materials has triggered numerous opportunities for exploring light–matter interactions and magneto-optical phenomena in the two-dimensional limit. In this paper, the excited state electronic, optical, and magneto-optical properties of monolayer nickel dichloride (), as a member of the family of two-dimensional ferromagnetic semiconductors, are studied using highly accurate many-body Green’s function perturbation theory. We compute the quasiparticle energies, dielectric function tensor, optical absorption spectrum, magnetic circular dichroism, and magneto-optical Kerr and Faraday spectra through the full-spinor GW and GW plus Bethe–Salpeter equation (GW+BSE) methods. Due to reduced screening in two-dimensional and the presence of highly localized d orbitals in Ni, monolayer exhibits enhanced self-energy corrections in the ground state band structure and strong excitonic effects dominating the optical and magneto-optical responses. Also to mimic the experimental setup, we provide a detailed theoretical formalism based on the transfer matrix method for simulating these signals in van der Waals heterostructures including monolayer . We observe that the illumination wavelength and the thickness of layers composing the van der Waals heterostructure can be used to engineer the magnitude and sign of magneto-optical signals.

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