The spin-polarized generalized gradient approximation（GGA）＋U approach was employed to study the bonding characteristics and magnetic coupling interactions in room-temperature phase α＇-NaV2O5. The calculated resui...The spin-polarized generalized gradient approximation（GGA）＋U approach was employed to study the bonding characteristics and magnetic coupling interactions in room-temperature phase α＇-NaV2O5. The calculated resuits indicate that the Vdry orbital is split off from other 3d orbitals in the VO5 pyramidal ligand field. The Vdry orbitals are hybridized strongly with the Opx/py orbitals, forming a V--O--V π bond in the ab plane. The ligand field effect together with the intra-atomic exchange splitting results in the insulating behavior. With the aid of Noodleman＇s bro- ken symmetry methods, the magnetic exchange constant was derived from mapping the relative energies onto the Heisenberg model. The antiferromagnetic（AFM） exchange energy, d, along the chain was calculated to be -593 K in good agreement with the experimental data.展开更多
基金Supported by the National Natural Science Foundation of China(No.50672031)the Program for Changjiang Scholar and Innovative Research Team in Universities of China(No.IRT0625)the Scientific and Technologic Research and Development Program of Jilin Province, China(No.20060511).
文摘The spin-polarized generalized gradient approximation（GGA）＋U approach was employed to study the bonding characteristics and magnetic coupling interactions in room-temperature phase α＇-NaV2O5. The calculated resuits indicate that the Vdry orbital is split off from other 3d orbitals in the VO5 pyramidal ligand field. The Vdry orbitals are hybridized strongly with the Opx/py orbitals, forming a V--O--V π bond in the ab plane. The ligand field effect together with the intra-atomic exchange splitting results in the insulating behavior. With the aid of Noodleman＇s bro- ken symmetry methods, the magnetic exchange constant was derived from mapping the relative energies onto the Heisenberg model. The antiferromagnetic（AFM） exchange energy, d, along the chain was calculated to be -593 K in good agreement with the experimental data.
