Use of density functional theory to investigate the optical and magnetic behaviours of Ge1-xMnxTe half-metallic ferromagnets

• Published in: Materials research bulletin 2020-03, Vol.123, p.110706, Article 110706
• Main Authors: Hassan, M., Mahmood, Q., Ramay, S.M.
• Format: Article
• Language: English
• Subjects: Half-metallic ferromagnets; Narrow band gap; Optical properties; Pd-Hybridization
• ISSN: 0025-5408; 1873-4227
• DOI: 10.1016/j.materresbull.2019.110706

[Display omitted] •The exchange splitting caused by pd-hybridization mediates ferromagnetism.•The RKKY coupling and half-metallic nature also cause ferromagnetism.•Structural symmetry strongly influences the computed physical properties.•The computed narrow band gaps also suggest useful optical device applications. Ge1-xMnxTe-based IVVI ferromagnetic semiconductors are attractive due to their versatile material properties. In this study, we investigate the physical properties of Ge1-xMnxTe with xMn≤ 0.50 using density functional theory. The dominant exchange splitting caused by pd-hybridisation mediates ferromagnetism that is consistent with the stable ferromagnetic (FM) states, as observed using structural optimisations. The presence of holes due to the half-metallic character suggests that RKKY interactions stabilise FM states. The absorption edges lie in the infrared energy range and are influenced by the crystal symmetry, and the compounds exhibit strong absorption of visible and UV energies. The narrow band gaps extracted from the band structures and the Tauc plots show similar variations with the Mn content, and hence suggest applications in optoelectronic devices.