Effects of magnetic impurity concentration and hole carriers on ferromagnetic stability of Li(ZnCr)As and Li(ZnCrCu)As

First-principles calculations were performed to study electronic structure and magnetic properties of Li(ZnCr)As and Li(ZnCrCu)As. The ground state of Li(ZnCr)As was ferromagnetism. To enhance the ferromagnetic stability of the doping system, two methods were proposed and the exchange mechanism was analyzed. More Cr impurities increased the energy gain and decreased p-d hybridization, contributing to the double-exchange interaction and thus promoting ferromagnetic stability of Li(ZnCr)As. By substituting Zn(3d¹⁰4s²) with Cu(3d¹⁰4s¹), additional hole carriers were introduced and the ferromagnetism was more stable than that in the single Cr doping case. The ferromagnetism of Li(ZnCrCu)As system was further stabilized with the increase of hole carrier concentration. The Li₃₂(Zn₂₂Cr₈Cu₂)As₃₂ configuration showed the strongest ferromagnetic stability. Therefore, it was possible to fabricate a new type of dilute magnetic semiconductor material with high ferromagnetic stability by adjusting the concentration of Cr impurity and additional hole carriers.