488 research outputs found
Electronic structure and orbital polarization of LaNiO with a reduced coordination and under strain: first-principles study
First-principles density functional theory calculations have been performed
to understand the electronic structure and orbital polarization of LaNiO
with a reduced coordination and under strain. From the slab calculation to
simulate [001] surface, it is found that orbital occupation is
significantly enhanced relative to occupation owing to the
reduced coordination along the perpendicular direction to the sample plane.
Furthermore, the sign of the orbital polarization does not change under
external strain. The results are discussed in comparison to the bulk and
heterostructure cases, which sheds new light on the understanding of the
available experimental data.Comment: Phys. Rev. B (in press
Competition between structural distortion and magnetic moment formation in fullerene C
We investigated the effect of on-site Coulomb interactions on the structural
and magnetic ground state of the fullerene C based on
density-functional-theory calculations within the local density approximation
plus on-site Coulomb corrections (LDA+). The total energies of the high
symmetry () and distorted () structures of C were
calculated for different spin configurations. The ground state configurations
were found to depend on the forms of exchange-correlation potentials and the
on-site Coulomb interaction parameter , reflecting the subtle nature of the
competition between Jahn-Teller distortion and magnetic instability in
fullerene C. While the non-magnetic state of the distorted
structure is robust for small , a magnetic ground state of the undistorted
structure emerges for larger than 4 eV when the LDA
exchange-correlation potential is employed.Comment: 4 figures, 1 tabl
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