Rhombohedral HoNiO3: A new half-metallic material with a high T, full spin-polarization and multiple Dirac-cones for advanced functional applications

Abstract

Abstract A recent work by Du et al. [ACS Applied Materials & Interfaces 10 (2018): 36088-36093] showed that LaMnO3 was a novel Dirac half metal with multiple Dirac cones. Our current work was based on their study, and the main task of our manuscript was to predict a new R 3 ¯ c phase material, HoNiO3, with 100% spin-polarization and multiple Dirac-cones from first principles. The magnetic states, including FM, NM and AFM, were examined by building a 1 × 1 × 1 unit cell and two superlattice cells, i.e., 1 × 1 × 2 and 2 × 2 × 1 systems. The results showed that the FM state was the most stable magnetic state for this system. From mean-field theory (MFT), we roughly estimated the Curie temperature of the HoNiO3 material. Although the real Curie temperature of a material is often overestimated by MFT, the high Curie temperature (TC) value of HoNiO3 (∼902.04 K) ensured that the TC of the material was higher than room temperature. Furthermore, the effect of spin-orbit coupling was added to examine the stabilities of the multiple Dirac cones. The results indicate that this material has long-term spin coherence, which is favourable for spin transport. The effects of the on-site Coulomb interaction U and on-site exchange constant J values on the electronic structures and magnetic moments were also examined. Moreover, the thermodynamic properties under different temperatures and pressures were investigated. We believe our current work will trigger further experimental and theoretical research on R 3 ¯ c -type Dirac half-metallic materials with multiple Dirac cones.