Magnetic and electronic properties of two-dimensional metal-organic frameworks TM₃(C₂NH)₁₂

The ferromagnetism of two-dimensional (2D) materials has aroused great interest in recent years, which may play an important role in the next-generation magnetic devices. Herein, a series of 2D transition metal-organic framework materials (TM-NH MOF, TM=Sc-Zn) are designed, and their electronic and magnetic characters are systematically studied by means of first-principles calculations. Their structural stabilities are examined through binding energies and ab-initio molecular dynamics simulations. Their optimized lattice constants are correlated to the central TM atoms. These 2D TM-NH MOF nanosheets exhibit various electronic and magnetic performances owing to the effective charge transfer and interaction between TM atoms and graphene linkers. Interestingly, Ni- and Zn-NH MOFs are nonmagnetic semiconductors (SM) with band gaps of 0.41 eV and 0.61 eV, respectively. Co- and Cu-NH MOFs are bipolar magnetic semiconductors (BMS), while Fe-NH MOF monolayer is a half-semiconductor (HSM). Furthermore, the elastic strain could tune their magnetic behaviors and transformation, which ascribes to the charge redistribution of TM-3d states. This work predicts several new 2D magnetic MOF materials, which are promising for applications in spintronics and nanoelectronics.