Room-temperature half-metallicity in rich Ti-alloyed CrSi2N4 monolayer

• Published in: Journal of magnetism and magnetic materials 2022-11, Vol.562, Article 169742
• Main Authors: Zhou, Haowen, Tang, Hui, Yuan, Hongkuan, Chen, Hong
• Format: Article
• Language: English
• Subjects: Alloying; Curie temperature; Ferromagnetism; Half-metallicity
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2022.169742

A new family of MoSi2N4-type monolayers have been extensively studied since it was recently synthesized, but half-metallic behavior is observed infrequently and unstable in the new family. Here, based on antiferromagnetic semiconductor CrSi2N4 monolayer, we predict a ferromagnetic half-metallicity (FHM) in alloy compound TiCrSi4N8 monolayer with a minority-spin gap of 3eV and a considerable magnetic anisotropy energy by applying first-principles calculations. The FHM of TiCrSi4N8 are robust against biaxial strain from −3% to 3%. The TiCrSi4N8 belongs to XY ferromagnet with negligible in-plane magnetocrystalline anisotropy and the Curie temperature is estimated to be near room temperature by Monte Carlo simulation with the consideration of symmetric and antisymmetric exchange interactions. Such a FHM at room temperature may be permitted in the range of Ti concentrations from 0.5 to 0.75. Strong d−−d hybridization between Cr and Ti atoms and the larger exchange splitting of Cr-d orbitals with respect to Ti-d orbitals are origin of the HM and magnetic moment of Cr atom, and ferromagnetic coupling between Cr atoms is due to the Cr–N–Cr superexchange interaction. Besides, the applied potentials of TiCrSi4N8 are further expanded by the large Young’s modulus and strong bending resistance. Thus, the rich Ti-alloyed CrSi2N4 monolayers are noteworthy candidates for generating spin current source. [Display omitted] •Alloy compound monolayers TixCr1−xSi2N4 (0.5≤x≤0.75) (R-TCSN) exhibit ferromagnetic half-metallicity.•R-TCSN belong XY ferromagnet and their Curie temperature is estimated to be near the room temperature.•Ferromagnetic half-metallic behavior of R-TCSN is robust against the biaxial strain.