With decreasing temperature, the magnetic metal NaV6O11 undergoes two structural phase transitions (at 245 and 40 K) and exhibits anomalous electrical and magnetic properties. To probe the origin of these structural, electrical, and magnetic properties, the electronic structures of NaV6O11 were calculated for its crystal structures at room temperature, 200 K, and 30 K using the extended Hückel tight-binding band method. The 245 and 40 K structural phase transitions are not caused by a charge density wave instability, but by the lowering of the energy levels lying well below the Fermi level. In the magnetic metallic state of NaV6O11, obtained by the spin-polarization of the partially filled d-block bands, the electrical conductivity of NaV5O11 is predicted to be greater along the c-direction than in the ab plane, in agreement with experiment. Our study indicates that the unpaired electrons of NaV6O11 reside mainly in the V3O11 rather than in the V3O8 layers. The anomalies of the p⊥-vs-T plot is explained by considering the effect of disordered magnetic moments on electrical conductivity.
ASJC Scopus subject areas
- Colloid and Surface Chemistry