Electric field modulated half-metallicity of semichlorinated GaN nanosheets

• Two-bilayer GaN nanosheet with chlorinated surface Ga atoms is a ferromagnetic metal.
• Semichlorinated GaN nanosheets exhibit ferromagnetic states under electric field.
• The half-metallic behaviors depend on the strength of electric field.
• The total magnetic moment varies with electric field, induced by unpaired N atoms.
• Our work offers an effective way to facilitate the tunable design in novel spintronics.

Through density-functional theory calculations, we investigated the half-metallic properties of semichlorinated gallium nitride (Cl–GaN) nanosheets (NSs) under an electric field F. The results show that the electric field can modulate Cl–GaN NSs efficiently from ferromagnetic metals to half-metals. More interestingly, under a broad range of electric field intensity (−0.10~−1.30 V/Å), Cl–GaN NSs have the excellently half-metallic properties with the band gaps (3.71–0.96 eV) and maximal half-metallic gaps with 0.30 eV in spin-up states and metallic behaviors in spin-down states. Moreover, the total magnetic moment decreases (increases) depending on the negative (positive) F, mainly induced by the unpaired N atoms. Our studies demonstrate that the electronic and magnetic properties of GaN NSs can be delicately tuned by the combined surface modification and electric field, indicating the potential of GaN NSs for developing high-performance spintronic nanodevices.