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Non-Landau Damping of Magnetic Excitations in Systems with Localized and Itinerant Electrons

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posted on 01.10.2015, 10:29 authored by Andrey Chubukov, Joseph BetourasJoseph Betouras, Dmitry V. Efremov
We discuss the form of the damping of magnetic excitations in a metal near a ferromagnetic instability. The paramagnon theory predicts that the damping term should have the form γ(q,Ω)â̂ Ω/Γ(q), with Γ(q)â̂ q (the Landau damping). However, the experiments on uranium metallic compounds UGe2 and UCoGe showed that Γ(q) is essentially independent of q. A nonzero γ(q=0,Ω) is impossible in systems with one type of carrier (either localized or itinerant) because it would violate the spin conservation. It has been conjectured recently that a near-constant Γ(q) in UGe2 and UCoGe may be due to the presence of both localized and itinerant electrons in these materials, with ferromagnetism involving predominantly localized spins. We present the microscopic analysis of the damping of near-critical localized excitations due to interaction with itinerant carriers. We show explicitly how the presence of two types of electrons breaks the cancellation between the contributions to Γ(0) from the self-energy and vertex correction insertions into the spin polarization bubble. We compare our theory with the available experimental data. © 2014 American Physical Society.

Funding

This work was supported by DOE Grant No. DE-FG02-ER46900 and by a Leverhulme Visiting Professorship held at the University of Loughborough (A. V. C.). J. J. B. was supported by the EPSRC Grant No. EP/H049797/1.

History

School

  • Science

Department

  • Physics

Published in

Physical Review Letters

Volume

112

Issue

3

Citation

CHUBUKOV, A., BETOURAS, J.J. and EFREMOV, D.V., 2014. Non-Landau damping of magnetic excitations in systems with localized and itinerant electrons. Physical Review Letters, 112 (3), 037202, DOI: 10.1103/PhysRevLett.112.037202

Publisher

© American Physical Society

Version

AM (Accepted Manuscript)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/

Publication date

2014-01-23

Notes

This article was published in the journal, Physical Review Letters [© American Physical Society] and the definitive version is available at: http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.112.037202

ISSN

0031-9007

eISSN

1079-7114

Language

en

Article number

037202

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