分子磁体电子结构及磁性质的探究-凝聚态物理专业论文.docxVIP

华 中 科 技 大 学 硕 士 学 位 论 文 II II Abstract In this thesis, we adopt the full potential linearized augmented plane wave (FP-LAPW) method based on the density-functional theory (DFT) to research the electronic structure and the magnetic properties of the non－pure molecular-based magnet Co(PhPO3)?H2O. We also studied the bulk properties and the electronic band structures of both phases, zinc-blende (ZB) and wurtzite (WZ), of aluminum nitride with the same method. The first-principles studies of non － pure molecular-based magnetic materials Co(PhPO3)?H2O revealed that: the compound Co(PhPO3)?H2O has a stable antiferromagnetic ground state and a ferromagnetic metastable state, which is consistent ?with the experiment; the spin magnetic moment of Co(PhPO3)·H2O is about 4.93 B ?  per molecule, which is in good agreement with the experimental value(5.01 ?B ); the major part of the spin magnetic moment is from the 3d7 configuration Co(II); the Co atom is the metallic magnetic center of the compound Co(PhPO3)·H2O; there are relatively smaller positive spin populations on the non-magnetic P, O1, O2, O3 atoms, which can be explained by the spin delocalization mechanism; in the inorganic layers of Co(PhPO3)·H2O, the octahedral coordinate of Co atom make a cross-linked Co-O network, there are strong interactions along two different approximately 1800 Co-O-Co superexchange paths; the antiferromagnetic interaction between Co atoms passes through the p orbitals of the O(O2) ligands near Co atoms; furthermore, both the AFM ground state and the FM metastable state of Co(PhPO3)·H2O are metal, and it is a organic conductor. As for AlN, we employed the local density approximation (LDA) and the PBE96 form of the generalized gradient approximation (GGA) for the exchange correlation potential to calculate its bulk properties, including the equilibrium lattice parameters, bulk modulus, cohesive energies and the total energies, and the band structures are also r