Beyond standard local density approximation in the study of magnetoelectric effects in Fe/BaTiO3 and Co/BaTiO3 interfaces

First-principles density functional theory (DFT) simulations for Fe/BaTiO3 and Co/BaTiO3 junctions have been performed with different treatments of the exchange-correlation potential, ranging from standard semilocal density approximations to a Hubbard-like approach and to hybrid functionals. With the aim of elucidating the role of correlations in the microscopic interplay between ferroelectricity and magnetism in the interfacial region, we find that, compared to standard DFT approximations, Hubbard-like approaches and hybrid functionals do not qualitatively modify the physical origin behind magnetoelectric effects driven by interfacial orbital hybridization. Rather, more accurate treatments of correlations for both Fe/BaTiO3 and Co/BaTiO3 interfaces predict a stronger change of the interface magnetization upon switching the direction of polarization in the ferroelectric layer.