TY - JOUR
T1 - FeMo double perovskite
T2 - From small clusters to bulk material
AU - Carvajal, E.
AU - Oviedo-Roa, R.
AU - Cruz-Irisson, M.
AU - Navarro, O.
PY - 2012/9/20
Y1 - 2012/9/20
N2 - To understand the differences in behaviour between up- and down-spin electrons observed in the half-metallic Sr2FeMoO6 double perovskite, the density of states (DOS) was studied for the (FeO 6)-4 and (MoO6)-6 octahedral clusters using first-principles density functional theory within the generalised gradient approximation (GGA) scheme and the Perdew-Burke-Ernzerhof (PBE) functional. Our results reveal that half-metallic character is present, even starting from an isolated (FeO6)-4 cluster, and is a consequence of spin decoupling of antibonding hybridisations between iron t 2g states and oxygen p states (t2ga states), i.e., t2ga states lie below the Highest Occupied Molecular Orbital (HOMO) in the up-spin channel, whereas they lie above the HOMO level in the down-spin channel. The spin-induced shifting between up-spin and down-spin DOS situates the HOMO in such a way that the molecular orbitals oxygen p states (p bands) are fully spin-paired by octet electrons. Thus, the down-spin channel has metallic character because the HOMO lies just at the p bands, and the up-spin channel is semiconducting because the HOMO falls within the energy gap between the t2ga and ega bands. Finally, the (MoO6)-6 octahedron does not inhibit the perovskite half-metallic character since this cluster has a zero total spin.
AB - To understand the differences in behaviour between up- and down-spin electrons observed in the half-metallic Sr2FeMoO6 double perovskite, the density of states (DOS) was studied for the (FeO 6)-4 and (MoO6)-6 octahedral clusters using first-principles density functional theory within the generalised gradient approximation (GGA) scheme and the Perdew-Burke-Ernzerhof (PBE) functional. Our results reveal that half-metallic character is present, even starting from an isolated (FeO6)-4 cluster, and is a consequence of spin decoupling of antibonding hybridisations between iron t 2g states and oxygen p states (t2ga states), i.e., t2ga states lie below the Highest Occupied Molecular Orbital (HOMO) in the up-spin channel, whereas they lie above the HOMO level in the down-spin channel. The spin-induced shifting between up-spin and down-spin DOS situates the HOMO in such a way that the molecular orbitals oxygen p states (p bands) are fully spin-paired by octet electrons. Thus, the down-spin channel has metallic character because the HOMO lies just at the p bands, and the up-spin channel is semiconducting because the HOMO falls within the energy gap between the t2ga and ega bands. Finally, the (MoO6)-6 octahedron does not inhibit the perovskite half-metallic character since this cluster has a zero total spin.
KW - Bulk material
KW - Density functional theory
KW - Double perovskites
KW - Half-metallic ferromagnetism
KW - Small clusters
UR - http://www.scopus.com/inward/record.url?scp=84866044476&partnerID=8YFLogxK
U2 - 10.1016/j.mseb.2012.03.041
DO - 10.1016/j.mseb.2012.03.041
M3 - Artículo
AN - SCOPUS:84866044476
SN - 0921-5107
VL - 177
SP - 1514
EP - 1517
JO - Materials Science and Engineering B: Solid-State Materials for Advanced Technology
JF - Materials Science and Engineering B: Solid-State Materials for Advanced Technology
IS - 16
ER -