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arXiv · 0909.2207

The double life of electrons in magnetic iron pnictides, as revealed by NMR

Andrew Smerald·Nic Shannon
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Abstract

We present a phenomenological, two-fluid approach to understanding the magnetic excitations in Fe pnictides, in which a paramagnetic fluid with gapless, incoherent particle-hole excitations coexists with an antiferromagnetic fluid with gapped, coherent spin wave excitations. We show that this two-fluid phenomenology provides an excellent quantitative description of NMR data for magnetic "122" pnictides, and argue that it finds a natural justification in LSDA and spin density wave calculations. We further use this phenomenology to estimate the maximum renormalisation of the ordered moment that can follow from low-energy spin fluctuations in Fe pnictides. We find that this is too small to account for the discrepancy between ab intio calculations and neutron scattering measurements.

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Andrew Smerald, Nic Shannon. 2010-11-03. The double life of electrons in magnetic iron pnictides, as revealed by NMR. https://doi.org/10.1209/0295-5075%2F92%2F47005

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