First principles studies of Fe adatoms on two-dimensional ferroelectric In₂Se₃ layer

Magnetic adatoms on surfaces may function as single-atom magnets with significant magnetization and coercivity at low temperatures [1]. Such systems can have potential applications in high-density magnetic memory and quantum information science technologies if adatom magnetization can be reliably controlled and detected. In this work, we investigate structural, electronic, and magnetic properties of Fe atoms adsorbed on a surface of two-dimensional ferroelectric α-In₂Se₃ using ab initio electronic structure methods and microscopic models. Preferred adsorption sites are identified for both In₂Se₃ electric polarization directions, and hopping energy barriers are computed. The interplay between adatom properties, the adsorption site, and the In₂Se₃ polarization is then investigated. We demonstrate that the difference in geometry between the competing adsorption sites significantly changes hybridization between the Fe orbitals and In₂Se₃ states. Consequently, the adatom electronic structure, magnetic moment, and magnetic anisotropy show a strong dependence on the adsorption site and can be effectively controlled by switching the electric polarization of the In₂Se₃ layer. This behavior can be potentially utilized to efficiently manipulate the adatom spin states with voltage.

[1] F. Donati, S. Rusponi, S. Stepanow, et al. Science 352, 318 (2016).