Journal Article

PreJuSER-20759

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Interplay of low-energy phonons and magnetiv excitations in the Kondo insulator YbB12

Alekseev, P. A. ; Mignot, J.-M. ; Nemkovski, K. S.FZJ* ; Rybina, A. V. ; Lazukov, V. N. ; Ivanov, A. S. ; Iga, F. ; Takabatake, T.

2012
IOP Publ. Bristol

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Please use a persistent id in citations: doi:10.1088/0953-8984/24/20/205601

Abstract: Peculiarities in the lattice dynamics of the Kondo insulator Y bB(12) have been studied by inelastic neutron scattering. Selected phonon modes were traced above and below the temperature region (T ~ 50 K) where the gap opens in the electron density of states. The intensities of some low-energy modes exhibit an anomalous temperature dependence for q vectors close to the Brillouin zone boundary, suggesting a renormalization of the phonon eigenvectors. This effect is thought to arise from a coupling with magnetic excitations of the same symmetry, which exist at nearby energies. It is argued that this magnetovibrational coupling may in turn play a role in the steep temperature crossover existing in Y bB(12) between the low-temperature (Kondo insulator) and high-temperature (incoherent spin-fluctuation) regimes, which is rapidly suppressed by lighter Zr substitution.

Keyword(s): Basic research (1st) ; Others (1st) ; Condensed Matter Physics (2nd) ; J

Note: We are grateful to D Reznik for fruitful discussions and to the LLB and ILL for hospitality during the experiments. Financial support from RFBR grants 08-02-00430 and 11-02-00121 is highly appreciated.

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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 (FUEK412) (FUEK412)
2. 544 - In-house Research with PNI (POF2-544) (POF2-544)

Experiment(s):

1. External Measurement

Appears in the scientific report 2012

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Database coverage:
; Current Contents - Social and Behavioral Sciences ; JCR ; Nationallizenz ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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