Disorder effects on hot spots in electron-doped cuprates

Computational modeling of the defect structure, hyperfine and magnetic properties of the Mn2+-doped magnetite of the composition Mn Fe3-O4 (y = ⅔ x)

“…For the structure where the extra Mn 2+ ions occupy interstitial sites (model 2a), the sharp spin-down states (Figure 6), that are related to the Fe 2+ minority charge at B1a, become localized and slightly shifted away from the Fermi-level, whereas those due to Fe 2+ at B4 become less localized as the band becomes broader. This could be ascribed to contributions to the band from the Mn 2+ ions that have higher energy levels compared to those of Fe 2+ /Fe 3+ [55]. For the structural model wherein the extra Mn 2+ substitute for tetrahedral Fe 3+ (model 6a), the few states formed at the bottom of the conduction band, which are mainly associated with the empty Fe 3+ t2g spin-down states, could imply the reduction of Fe 3+ at the interstitial and B3 sites to Fe 2+ .…”

“…For the structural model wherein the extra Mn 2+ substitute for tetrahedral Fe 3+ (model 6a), the few states formed at the bottom of the conduction band, which are mainly associated with the empty Fe 3+ t2g spin-down states, could imply the reduction of Fe 3+ at the interstitial and B3 sites to Fe 2+ . Alternatively, they could reflect the effect of introducing the Mn 2+ ions into the Fe3O4 structure with their higher energy levels relative to those of the substituted Fe 3+ [55] .…”