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Two-dimensional charge order in layered 2-1-4 perovskite oxides

Shigeki Onoda·Yukitoshi Motome·Naoto Nagaosa
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Abstract

Monte Carlo simulations are performed on the three-dimensional (3D) Ising model with the 2-1-4 layered perovskite structure as a minimal model for checkerboard charge ordering phenomena in layered perovskite oxides. Due to the interlayer frustration, only 2D long-range order emerges with a finite correlation length along the c axis. Critical exponents of the transition change continuously as a function of the interlayer coupling constant. The interlayer long-range Coulomb interaction decays exponentially and is negligible even between the second-neighbor layers. Instead, monoclinic distortion of a tetragonal unit cell lifts the macroscopic degeneracy to induce a 3D charge ordering. The dimensionality of the charge order in La$_{0.5}$Sr$_{1.5}$MnO$_4$ is discussed from this viewpoint.

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Shigeki Onoda, Yukitoshi Motome, Naoto Nagaosa. 2004-02-02. Two-dimensional charge order in layered 2-1-4 perovskite oxides. https://doi.org/10.1103/physrevlett.92.236403

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