Charge disproportionation (CD) and spin differentiation in Na(1/2)CoO2 are studied using the correlated band local-density approximation + Hubbard U (LDA+U) approach. The simultaneous CD and gap opening seen previously is followed in detail through a first-order charge disproportionation transition 2Co(3.5+)-->Co3++Co4+. Disproportionation in the Co a(g) orbital results in half of the ions (Co3...

We study the polarization induced via spin-orbit interaction by a magnetic cycloidal order in orthorhombic TbMnO3 using first-principle methods. The case of magnetic spiral lying in the bc plane is analyzed, in which the pure electronic contribution to the polarization is shown to be small. We focus our attention on the lattice-mediated contribution, and study it’s dependence on the Coulomb int...

Doping evolution of the Fermi surface topology of Na(x)CoO(2) is studied systematically. Both local density approximation (LDA) and local spin density approximation (LSDA) predict a large Fermi surface as well as small hole pockets for doping levels x approximately 0.5. In contrast, the hole pockets are completely absent for all doping levels within LSDA+U. More importantly, we find no violatio...

The measurement and analysis of fifty-two elements by quadrupole inductively coupled plasma mass spectrometry (Q-ICP-MS) direct mercury were applied to origin discrimination Italian traditional cuttlefish (Chioggia, Venice lagoon) from Mediterranean Atlantic samples. A total 68 specimens analyzed in triplicates generate 204 spectra profiles which statistically processed different chemometric te...

Local density approximation + Hubbard U (LDA + U) band structure calculations reveal that magnetite (Fe3O4) forms an insulating charge-orbital-ordered state below the Verwey transition temperature. The calculated charge ordering is in good agreement with that inferred from recent experiments. We found an associated t(2g) orbital ordering on the octahedral Fe2+ sublattice. Such an orbital orderi...