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arXiv · 2301.08821

Electron Doping of a Double Perovskite Flat-band System

Lun Jin·Nicodemos Varnava·Danrui Ni·Xin Gui·Xianghan Xu·Yuanfeng Xu·B. Andrei Bernevig·Robert. J. Cava
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Abstract

Electronic structure calculations indicate that the Sr2FeSbO6 double perovskite has a flat-band set just above the Fermi level that includes contributions from ordinary sub-bands with weak kinetic electron hopping plus a flat sub-band that can be attributed to the lattice geometry and orbital interference. To place the Fermi energy in that flat band, electron doped samples with formulas Sr2-xLaxFeSbO6 (0 < x < 0.3) were synthesized and their magnetism and ambient temperature crystal structures determined by high-resolution synchrotron X-ray powder diffraction. All materials appear to display an antiferromagnetic-like maximum in the magnetic susceptibility, but the dominant spin coupling evolves from antiferromagnetic to ferromagnetic on electron doping. Which of the three sub-bands or combinations is responsible for the behavior has not been determined.

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Lun Jin, Nicodemos Varnava, Danrui Ni, Xin Gui, Xianghan Xu, Yuanfeng Xu, B. Andrei Bernevig, Robert. J. Cava. 2023-01-20. Electron Doping of a Double Perovskite Flat-band System. https://doi.org/10.1073/pnas.2218997120

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