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arXiv · 1405.3395

Strange magnetic multipoles and neutron diffraction by an iridate perovskite (Sr2IrO4)

S W Lovesey·D D Khalyavin
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Abstract

A theoretical investigation of a plausible construct for electronic structure in iridate perovskites demonstrates the existence of magnetic multipoles hitherto not identified. The strange multipoles, which are parity-even, time-odd and even rank tensors, are absent from the so-called jeff = 1/2 model. We prove that the strange multipoles contribute to magnetic neutron diffraction, and we estimate their contribution to intensities of Bragg spots for Sr2IrO4. The construct encompasses the jeff = 1/2 model, and it is consistent with the known magnetic structure, ordered magnetic moment, and published resonant x-ray Bragg diffraction data. Over and above time-odd quadrupoles and hexadecapoles, whose contribution changes neutron Bragg intensities by an order of magnitude, according to our estimates, are relatively small triakontadipoles recently proposed as the primary magnetic order-parameter of Sr2IrO4.

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S W Lovesey, D D Khalyavin. 2014-05-14. Strange magnetic multipoles and neutron diffraction by an iridate perovskite (Sr2IrO4). https://arxiv.org/abs/1405.3395

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