Berlin 2012 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 39: Focussed session: Frontiers of electronic structure theory: Strong correlations from first principles III (jointly with TT)

O 39.6: Vortrag

Mittwoch, 28. März 2012, 11:45–12:00, HE 101

Magnetic charge-ordered bad-metal ground state of nickelate superlattices — Danilo Puggioni, Alessio Filippetti, and •Vincenzo Fiorentini — Dept of Physics, U of Cagliari and CNR-IOM, Cagliari, Italy

Short-period strained LaNiO₃/LaAlO₃ superlattices undergo paramagnetic–antiferromagnetic metal–“insulator” transitions at low temperature, with charge ordering signaled by spectral weight transfer and XAS line splitting. Further, DMFT calculations suggest that the Fermi surface may become a single hole-like cylinder similar to optimally-doped cuprates, quite unlike that of bulk LaNiO₃.

We report ab initio self-interaction-corrected density functional calculations showing that these superlattices are antiferromagnetic and charge-ordered. Although not gap-insulating, they show a sharp pseudo-gap at the Fermi energy, a dc conductivity 2 orders of magnitude lower than in the paramagnetic phase, and a joint density of states for vertical transitions kicking in near the experimental charge gap. While the paramagnetic state has a cuprate-like Fermi surface, the ground-state antiferromagnetic phase has a reconstructed, underdoped-cuprate-like Fermi surface with both electron and hole-like small pockets, at points known as “nodal” and “antinodal” in cuprates. We thus predict that these superlattices should exhibit quantum oscillations in magnetic field.