Journal Article

PreJuSER-15735

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Phonon Dynamics in Parent and Superconducting FeAs Compounds

Mittal, R. ; Zbiri, M. ; Rols, S. ; Su, Y.FZJ* ; Xiao, Y.FZJ* ; Chaplot, S. L. ; Schober, H. ; Johnson, M. ; Chatterji, T. ; Matsuishi, S. ; Hosono, H. ; Brückel, T.FZJ*

2011
Physical Society of the Republic of China Taipei

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Abstract: The comparison of the phonon spectra of the parent MFe2As2 (M = Ba, Ca, Sr) and MFeAsF (M = Ca, Sr) compounds show a very strong renormalization in the lower and intermediate frequency part of the vibrations. Mass effects and lattice contraction cannot solely explain these changes. Further, the measurement of temperature dependence of phonon density of states across the magnetic/structural phase transition temperature indicates that softening of low energy modes in the paramagnetic state of these compounds may be due to the interaction of phonons with electron or short-range spin fluctuations in the normal state of the superconducting compound as well as in the parent compound. Detailed lattice dynamical calculations are carried out to analyze the experimental data.

Keyword(s): Basic research (1st) ; Key Technologies (1st) ; Information Technology and Functional Materials (1st) ; Condensed Matter Physics (2nd) ; J

Note: Record converted from VDB: 12.11.2012

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Contributing Institute(s):

1. Streumethoden (PGI-4)
2. JCNS-FRM-II (JCNS (München) ; Jülich Centre for Neutron Science JCNS (München) ; JCNS-FRM-II)
3. Streumethoden (JCNS-2)

Research Program(s):

1. Grundlagen für zukünftige Informationstechnologien (P42)
2. Großgeräte für die Forschung mit Photonen, Neutronen und Ionen (PNI) (P55)

Experiment(s):

1. External Measurement

Appears in the scientific report 2011

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