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

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-fl...

Full description

Saved in:
Bibliographic Details
Published in:Europhysics letters 2010-11, Vol.92 (4), p.47005
Main Authors: Smerald, A, Shannon, N
Format: Article
Language:English
Subjects:
67.80.dk
75.50.Ee
76.60.Es
Excitation
Fluid dynamics
Fluid flow
Fluids
Iron
Mathematical analysis
Nuclear magnetic resonance
Phenomenology
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary: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 initio calculations and neutron scattering measurements.
ISSN:0295-5075
1286-4854
DOI:10.1209/0295-5075/92/47005