Effect of 4d transition metals on the electronic and magnetic properties of twin graphene.

• The doping of 4d-TM can regulate the electronic structures of TG. • The doping of Tc introduces half-metallic properties in TG. • Y, Mo, and Ag single-doped TG systems are dilute magnetic semiconductors. • The 4d-TM dual-doped TG systems exhibit different magnetic interactions (FM and AFM). • The dual-doping positions of Y and Rh atoms can switch the magnetic interaction. To explore new uses for twin graphene (TG) in spintronic devices, we tuned the electronic properties and introduced a magnetic moment for TG by doping it with 4d transition metal (TM = Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, and Cd) atoms. Some single TM doped TG systems have spin-polarized states, and their magnetic moments can be divided into three categories. TG doped with single Y, Mo, and Ag exhibits dilute magnetic semiconductor (DMS) properties, and the doping of Tc introduces a half-metallic character. For dual-doped systems, the electronic properties of TG can be effectively regulated by the doping positions of various TM atoms. The α-2Mo/TG, α-2Tc/TG, β-2Y/TG, and γ-2Y/TG systems exhibit DMS behavior. Some dual-doped systems exhibit antiferromagnetic (AFM) and ferromagnetic (FM) behaviors. For β configurations, the electronic properties of TM atoms dual-doped on the same and different sides of TG are similar to those of the corresponding single-doped systems, except for the β/D-2Zr/TG and β/D-2Ag/TG systems. The dual-doping of Y and Rh atoms on the same and different sides of TG can realize the switch between AFM and FM. The results of this study might provide new inspiration for applying TG in spintronic and nanomagnet devices. [ABSTRACT FROM AUTHOR]