Defect driven spin state transition and the existence of half-metallicity in CoO

Abstract

We unveil the native defect induced high spin to low spin state transition in and half-metallicity in CoO. First principles calculations unravel that, defect density holds a key role in dictating the spin-state transition in ion in CoO, and introducing the half-metallicity. Charge transfer in the vicinity of vacancy plane favors the stabilization and coexistence of bivalent and trivalent ion in CoO. We propose that defect engineering could serve as a route to design the half metallicity in transition metal mono-oxides.

Coexisting commensurate and incommensurate charge ordered phases in CoO

“…Cation defect-induced HM is also reported in other similar transition-metal mono-oxides, e.g. NiO, MnO, CaO 38 , 52 , 53 , 55 . The asymmetric nature of the DOS profile implies a deviation from the AFM nature.…”

“…half-metallicity, spin-blockade, spin-state crossover, ferromagnetism, etc, even in a simple stoichiometric transition-metal mono-oxides, e.g. CaO, MnO, NiO, CoO 38 , 48 , 52 – 55 . Therefore, motivated by an exceptional agreement between our experimental and simulated HR-TEM observations, and further guided by the earlier theoretical insights, we follow the route of cation order imperfection and computationally explore the feasibility of inducing CO in (Supplementary Information, Section III).…”

Co1–xFexOy Oxygen Evolution Nanocatalysts: On the Way To Resolve (Electro)Chemically Triggered Surface-Bulk Discrepancy

“…The rs-metal oxide is identified as rs-CoO for Co 0.99 (Fe 0.01 )O y and Co 0.80 Fe 0.20 O y . The rs-CoO of the latter is incorporated with Fe 3+ -ions, which are smaller sized than the typical highspin Co 2+ -ions in rs-CoO, 46,47 leading to a unit cell shrinking of Co 0.80 Fe 0.20 O y and explains the observed shift of its diffraction peaks toward higher 2θ relative to Co 0.99 (Fe 0.01 )O y (Figure 1b). A similar shift is observed when comparing the XRD peak positions from references of rs-Co 0.7 Fe 0.3 O and rs-CoO (Figure 1b).…”