We consider the influence of a nearest-neighbor Coulomb interaction in an extended Hubbard model and introduce an interaction term which simulates atomic polarizabilities. The inclusion of atomic polarizabilities in the model has the effect of screening the on-site Coulomb interaction for charged excitations, unlike a neighbor Coulomb interaction which reduces energies of neutral local excitations, leaving the conductivity gap unchanged. This is supported by an exact diagonalization study on small, mainly one-dimensional, extended Mott-Hubbard systems. For large V, the system undergoes a phase transition from a spin-density wave (SDW) to a charge-density wave (CDW). It is shown that the SDW/CDW phase transition cannot be described correctly when using effective parameters, but that screening effects have to be included explicitly. Also other phases, one of which is ferroelectric, appear when atomic polarizabilities are included in the model Hamiltonian. We study ${\mathrm{C}}_{60}$ in terms of the degenerate extended Hubbard model with screening effects.We consider the influence of a nearest-neighbor Coulomb interaction in an extended Hubbard model and introduce an interaction term which simulates atomic polarizabilities. The inclusion of atomic polarizabilities in the model has the effect of screening the on-site Coulomb interaction for charged excitations, unlike a neighbor Coulomb interaction which reduces energies of neutral local excitations, leaving the conductivity gap unchanged. This is supported by an exact diagonalization study on small, mainly one-dimensional, extended Mott-Hubbard systems. For large V, the system undergoes a phase transition from a spin-density wave (SDW) to a charge-density wave (CDW). It is shown that the SDW/CDW phase transition cannot be described correctly when using effective parameters, but that screening effects have to be included explicitly. Also other phases, one of which is ferroelectric, appear when atomic polarizabilities are included in the model Hamiltonian. We study ${\mathrm{C}}_{60}$ in terms of the degenerate extended Hubbard model with screening effects.

Physical review. B, Condensed matterJul 15, 199527 citations

Observing spin polarization in single atoms

Philip F. Schewe

Physics TodayOct 1, 20070 citations

New Phases in an Extended Hubbard Model Explicitly Including Atomic Polarizabilities

Jeroen van den Brink, M.B.J. Meinders, J. Lorenzana +2 more

We consider the influence of a nearest-neighbor Coulomb interaction in an extended Hubbard model and introduce a new interaction term which simulates atomic polarizabilities. This has the effect of screening the on-site Coulomb interaction for charged excitations, unlike a neighbor Coulomb interaction which reduces energies of locally neutral excitations. We find that the spin density to charge density wave phase transition, however, is determined by the unscreened on-site Coulomb repulsion. The order of this phase transition is affected by polarization. We show that new phases appear, one of which is ferroelectric, when atomic polarizabilities are explicitly included.We consider the influence of a nearest-neighbor Coulomb interaction in an extended Hubbard model and introduce a new interaction term which simulates atomic polarizabilities. This has the effect of screening the on-site Coulomb interaction for charged excitations, unlike a neighbor Coulomb interaction which reduces energies of locally neutral excitations. We find that the spin density to charge density wave phase transition, however, is determined by the unscreened on-site Coulomb repulsion. The order of this phase transition is affected by polarization. We show that new phases appear, one of which is ferroelectric, when atomic polarizabilities are explicitly included.

Physical Review LettersDec 18, 199555 citations

Anisotropy of the static dipole polarizability induced by the spin–orbit interaction: the S-state atoms N–Bi, Cr, Mo and Re

Alexei A. Buchachenko

A systematic ab initio study is performed on the ground state static dipole polarizabilities of the 2 S +1 S, S >1/2, atoms from N to Bi, Cr, Mo, Mn, Tc and Re. The benchmark scalar-relativistic values of the scalar polarizability components are obtained using the coupled cluster method. The spin–orbit configuration interaction calculations are carried out for the anisotropic (tensor) polarizability components of these atoms (except Mn and Tc) that arise from the second-order spin–orbit interaction. The tensor polarizabilities are calculated for the first time and found to increase from 10 −5 (N) to 3.8 atomic units (Bi) approximately as the fourth power of the nuclear charge. The simple correlations and implication to magnetic trapping of cold atoms are discussed.A systematic ab initio study is performed on the ground state static dipole polarizabilities of the 2 S +1 S, S >1/2, atoms from N to Bi, Cr, Mo, Mn, Tc and Re. The benchmark scalar-relativistic values of the scalar polarizability components are obtained using the coupled cluster method. The spin–orbit configuration interaction calculations are carried out for the anisotropic (tensor) polarizability components of these atoms (except Mn and Tc) that arise from the second-order spin–orbit interaction. The tensor polarizabilities are calculated for the first time and found to increase from 10 −5 (N) to 3.8 atomic units (Bi) approximately as the fourth power of the nuclear charge. The simple correlations and implication to magnetic trapping of cold atoms are discussed.

Proceedings of the Royal Society A Mathematical Physical and Engineering SciencesNov 17, 201018 citations

Spin-Polarized Atoms

Galina A. Nemova

SPIE eBooksNov 6, 20190 citations

{\mathrm{C}}_{60}

in terms of the degenerate extended Hubbard model with screening effects.