Improving the magnetic moment of CaGe and promoting the conversion of semiconductors to diluted magnetic semiconductors using Mn-doping.

The dilute magnetic properties of materials have important potential applications in the field of electronic science and technology. Intrinsic CaGe is a new environmentally friendly semiconductor material, and exhibits cubic and orthorhombic phases. The crystal structure characteristics of CaGe indicate that the modulation of its dilute magnetic properties can theoretically be achieved by doping with magnetic elements. The study of band structures shows that CaGe is a semiconductor, while Mn doped CaGe is a semi-metal. The results of density of states and atomic population analysis show that Mn doped CaGe exhibits ferrimagnetism with a magnetic moment of 5 , and the orbital splitting energy of the Mn atom is 1.0 eV. Mn-doping changes the cubic crystal field of CaGe, and the charge transfer and electron polarization of Ca d and Ge p orbitals are affected by Mn atoms. The Ca d orbital is split into d, d, d, d and d orbitals, and the contribution of spin of each d split orbital to the magnetic moment of the Ca d orbital is in the order d > d > d > d > d. The Ge p orbital is split into p, p and p orbitals, and the spin contribution of each p orbital to the magnetic moment of the Ge p orbital is in the order p > p > p. The analysis of atom populations shows that the charge transfer and spin of Ca and Ge change with Mn doping, and the difference between spin up and spin down increases, improving the magnetism of CaGe and forming a dilute magnetic semiconductor.