Effects of halogen substituted on the Mn-O electron transfer of NiMn2O4

Abstract

To observe the effect of halogen-substitution on the Mn-O electron transfer of NiMn2O4, we calculated Mn-mixed-valence configuration (charge-disproportionation) and oxygen vacancy by the density functional theory (DFT). The results indicate that the halogen-p5 state induces the O-2p orbital splitting to create an oxygen vacancy in the VB (valence band: about −5 eV). The oxygen vacancy can capture an electron from Mn[Formula: see text]-3d5 orbital that makes the Mn[Formula: see text]-3d5 change to Mn[Formula: see text]-3d4 states (Mn-charge disproportionate), and providing many effective-hole (40.14 [Formula: see text] 96.72 × 10[Formula: see text] kg). The halogen-p5-O-2p4 hybrid orbitals enhance the O-2p4-Mn-3d5 p-d hybrid orbital (about 19.18 electron). That increases the surface potential in Mn-O octahedron (for Cl-substituted: about 60 meV), the corresponding electron–electron interactions change from complex t[Formula: see text] (O-2p4-Mn[Formula: see text]-3d[Formula: see text] to complete [Formula: see text] (O-2p4-Mn[Formula: see text]-3d[Formula: see text]-e[Formula: see text](O-2p4-halogen-p5) orbital. This study effectively analyzes the microscopic changes of the electron transfer caused by the small amount of doping, provides a theoretical basis for the design of NMO-based semiconductor material.