Large perpendicular magnetic anisotropy in Ta/CoFeB/MgO on full coverage monolayer MoS2 and first principle study of its electronic structure

TL;DR

This study demonstrates the growth of Ta/CoFeB/MgO structures on monolayer MoS2 with large perpendicular magnetic anisotropy, supported by first-principles calculations showing tunable electronic structure, enabling room-temperature spin optoelectronic devices on 2D materials.

Contribution

It reports the experimental realization of large perpendicular magnetic anisotropy in Ta/CoFeB/MgO on monolayer MoS2 and provides first-principles insights into the electronic structure modifications.

Findings

Achieved a perpendicular interface anisotropy energy of 0.975 mJ/m².

MgO insertion prevents ferromagnetic atom diffusion into MoS2.

MgO thickness influences MoS2 band structure and proximity effects.

Abstract

Perpendicularly magnetized spin injector with high Curie temperature is a prerequisite for developing spin optoelectronic devices on 2D materials working at room temperature (RT) with zero applied magnetic field. Here, we report the growth of Ta/CoFeB/MgO structures with a large perpendicular magnetic anisotropy (PMA) on full coverage monolayer (ML) MoS2. A large perpendicular interface anisotropy energy of 0.975mJ/m2 has been obtained at the CoFeB/MgO interface, comparable to that observed in magnetic tunnel junction systems. It is found that the insertion of MgO between the ferromagnetic metal (FM) and the 2D material can effectively prevent the diffusion of the FM atoms into the 2D material. Moreover, the MoS2 ML favors a MgO(001) texture and plays a critical role to establish the large PMA. First principle calculations on a similar Fe/MgO/MoS2 structure reveal that the MgO thickness can modify the MoS2 band structure, from an indirect bandgap with 7ML-MgO to a direct bandgap with 3ML-MgO. Proximity effect induced by Fe results in a splitting of 10meV in the valence band at the {\Gamma} point for the 3ML-MgO structure while it is negligible for the 7ML-MgO structure. These results pave the way to develop RT spin optoelectronic devices on 2D transition-metal dichalcogenide materials.