Orbital ordering transition in the single-layer manganites near half doping: a weak-coupling approach

Abstract

The roles of crystal-field splitting and Jahn-Teller distortions on the orbital ordering transition are investigated in the single-layer manganites near half doping. Crystal-field splitting of energy levels favoring the $d_{3z^2-r^2}$ occupancy provides not only the correct Fermi surface topology for La${}_{0.5}$Sr${}_{1.5}$MnO${}_4$ having a circular electron pocket around the $\Gamma$ point, but also enhances the flatness of the hole pocket around the M point thereby improving the nesting. In the presence of the circular electron pocket, Jahn-Teller distortions are found to be crucial for the transition to the transverse orbital ordering with ordering wavevector ($0.5\pi ,0.5\pi$). In the hole-doping regime $0.5\le x\le 0.7$, the orbital ordering wavevector shows a linear dependence on the hole concentration in accordance with the experiments.

References in corpus (5)

• Orbital Fluctuation Mediated Superconductivity in Iron Pnictides: Analysis of Five Orbital Hubbard-Holstein Model
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Cited by in corpus (2)

• Charge order induced in an orbital density-wave state
• Effect of strain-induced orbital splitting on the magnetic excitations in undoped cuprates