The half-metallic characteristic of Cr-doped rutile germanium oxide-based dilute magnetic semiconductor predicted by first-principles calculations

This paper reported on the theoretical investigations with first principle calculations on the electronic and band structure properties of Cr-doped GeO 2 rutile. Firstly, it discussed the half-metallic characteristics of rutile GeO 2 (r-GeO 2 ) bulk crystal when this latter is doped with 3d-Cr transition metal. Secondly, and to understand the impact of doping Cr impurity, three amounts of Cr of 2, 6 and 10% were inserted in the r-GeO 2 lattice which showed how doping can improve the magnetic properties of the obtained dilute magnetic semiconductor. The theoretical calculations were performed in the general framework of the density functional theory within the Korringa–Kohn–Rostoker approach combined with the coherent potential approximation. We adopted the local density approximation (LDA) as well as the self-interaction corrected LDA (LDA-SIC) to account for the exchange and correlation in the strong correlated electron systems. Based on calculations within LDA and LDA-SIC approximations, it was found that the compound behaves as half-metal material. Moreover, we have studied the interaction responsible of magnetism using both LDA and LDA-SIC approximations. In addition, we calculated the exchange coupling parameters of the classical Heisenberg model and studied the X-ray absorption spectrum at the K-edge of Ge 1− x Cr x O 2 . The obtained values of Curie temperature were found above the ambient value once doping concentration exceeds 6%. Hence, it can be inferred that Cr-doped r-GeO 2 presents a good potential as a practical spintronic material when the doping concentration is greater than or equal to 6%.