Controllable magnetic anisotropy and ferroelasticity in superconducting FeSe monolayer with surface fluorine adsorption

TL;DR

This study uses density functional theory to explore how fluorine adsorption affects the magnetic, ferroelastic, and multiferroic properties of monolayer FeSe, revealing potential for advanced spintronic devices.

Contribution

It demonstrates how fluorine adsorption induces controllable magnetic anisotropy and ferroelasticity in FeSe monolayer, introducing a new pathway for multifunctional 2D spintronic materials.

Findings

Fluorine adsorption causes coverage-dependent magnetic anisotropy.

F/FeSe exhibits multiferroicity due to the Jahn-Teller effect.

Coupling between magnetism and ferroelasticity is identified.

Abstract

Controllable magnetization in atomically thin two-dimensional magnets is highly desirable for developing spintronics. For FeSe monolayer, its magnetic ground state is not yet fully understood, and the potential in constructing high-speed and advanced devices remains unknown. Using density functional theory calculations, we confirm the spin ordering of monolayer FeSe to be dimer texture. With Fluorine (F) adsorption (F/FeSe), the system exhibits a coverage dependent magnetic anisotropy and multiferroicity which can be attributable to the Jahn-Teller effect, being the benefit to potential spintronic applications. Intriguingly, an inherent coupling between magnetism and ferroelasticity in the most energetically favorable F/FeSe system is proposed. Our study thus not only provides a promising way to control the spintronic properties and construct multiferroics, but also renders F/FeSe an ideal platform for magnetism studies and practical high-performance multifunctional devices.