Tuning the Structural, Electronic, and Magnetic Properties of Germanene by the Adsorption of 3d Transition Metal Atoms

Abstract

The structural, electronic, and magnetic properties of 3d transition metal (TM) atoms (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn) adsorbed germanene are addressed using density functional theory. Based on the adsorption energy, TM atoms prefer to occupy at the hollow site for all the cases. The obtained values of the total magnetic moment vary from 0.97 to 4.95 μB in the case of Sc to Mn adsorption, respectively. A gap of 74 meV with a strongly enhanced splitting of 67 meV is obtained in case of Sc adsorption, whereas metallic states are obtained in case of Ti, Cr, Mn, Fe, and Co. Nonmagnetic states are realized for Ni, Cu, and Zn adsorption. Moreover, semiconducting nature is obtained for nonmagnetic cases with a gap of 26–28 meV. Importantly, it is found that V-adsorbed germanene can host the quantum anomalous Hall effect. The obtained results demonstrate that TM atoms and nearest-neighbor Ge atoms are ferromagnetically ordered in the cases of V, Mn, Fe, Co, Ni, Cu, and Zn, while antiferromagnetic ordering is obtained for Sc, Ti, and Cr. In addition, the effects of the coverage of all TM atoms on the electronic structure and the ferromagnetic and antiferromagnetic coupling in the case of Mn are examined. The results could help to understand the effect of TM atoms in a new class of two-dimensional materials beyond graphene and silicene.