Simulation of Fe$_{n}$-doped C$_{60}$ Monolayer on \textit{h}-BN/Ni (111)

We have performed first-principles calculations based on density functional theory to investigate the structure, electronic structure and magnetic properties of Fe$_{n}$-C$_{60}$ complexes. Interfaces that consist of a C$_{60}$ monolayer, a supporting h-BN/Ni (111) layers, and the transition metal Fe$_{n}$ ($n$ = 1-4 {\&} 15) have been thoroughly characterized. Electron transfer has been observed from the Fe ions to the C$_{60}$ molecules, which leads to the domination of ionic character on the Fe-C$_{60}$ bonding. Furthermore, the Fe$_{n}$-doped C$_{60}$ systems show strong hybridizations between s-, d- orbitals of Fe atoms and $p$-orbital (\textit{$\pi $}-like) of C atoms. The spin of the net transferred electrons from Fe$_{n}$ to C$_{60}$ is spin minority, which leads to a magnetic moment in C$_{60}$ opposite to the total magnetic moment of the system. All of the electronic structure calculations have been performed in generalized gradient approximation (GGA) and local density approximation (LDA). In Fe$_{4}$C$_{60}$ and Fe$_{15}$C$_{60}$ systems, we have also performed GGA+U and LDA+U calculations for comparison.