Where EFIM, EAFM1 and EAFM2 are the total energy of FIM, AFM1 and AFM2 configurations from DFT calculations. E0 is the total energy of systems without magnetic coupling. S is the projected magnetic moment of each magnetic atom. The magnetic coupling Hamiltonian and spin density for Ni2/CrBr3 are presented in the Figure . In addition, the J values of Ni8/CrBr3 are calculated by using the four-states method, and the detailed calculation procedure can be found in the Figure ). According to the Goodenough-Kanamori-Anderson (GKA) rules, when the bond angle between cation-anion-cation approaches 90 °, the superexchange interactions mediated by the anions should always result in FM coupling (see Figure ). The interactions between the nearest neighboring Ni-Ni atoms arise from direct metallic interactions within the layers.