Role of Ferroelectricity, Delocalization, and Occupancy of d States in the Electrical Control of Interface-Induced Magnetization

In this study, the influence of generalized-gradient-approximation (GGA) deficiencies, d-band occupancy, and itinerancy in the magnetoelectric (ME) effect is investigated from first principles by changing the interface composition of the Fe3Si/M/BaTiO3 heterostructure, where M stands for an atomic layer of pure 3d or 4d metals (from Sc to Cd). The lattice overestimation of the ferroelectric phase leads to the overestimation of the magnetoelectricity, which can be partially corrected by using the Perdew-Burke-Ernzerhof functional revised for solids. The inclusion of Hubbard-like corrections generally predicts larger changes of interface magnetization upon the reversal of polarization direction, although preserving the trends of plain GGA calculations. The itinerancy of 4d states does not favor the interface ME coupling due to the lower density of states near the Fermi level. Here, it is shown how the control of the d-state energy levels through their electronic occupancy has the potential to substantially enhance the interface ME effect induced by bonding effects. A substantial increase of magnetoelectricity in the Fe3Si/BaTiO3 heterostructure can be achieved by replacing interface Fe atoms with V or Mn.

Automated summary

This study investigates the influence of GGA deficiencies, d-band occupancy, and itinerancy on the magnetoelectric effect in Fe3Si/M/BaTiO3 heterostructures. It shows that modifying the interface composition can enhance magnetoelectricity and that controlling d-state energy levels and replacing certain metals can increase the interface ME effect.