Inelastic neutron scattering study of the lattice dynamics in the clathrate compound BaGe_5
Abstract
We report inelastic neutron scattering (INS) measurements on the polycrystalline oP60-type clathrate BaGe_5, whose crystal structure is related to the type-I clathrate Ba8Ge_(43□3) and to the cP124-clathrate Ba_6Ge_(25). Our results show that BaGe_5 exhibits a similar phonon density of states (PDOS) in the energy range 0–40 meV with respect to Ba8Ge_(43□3). The low-energy region of the PDOS spectrum (0–10 meV) consists of two peaks at 4.1 and 6.2 meV likely related to Ba-weighted modes. Compared to Ba8Ge_(43□3), the low-energy region of the phonon spectrum of BaGe_5 shows a more complex structure, likely reflecting the presence of three distinct crystallographic sites for Ba. The specific heat data of BaGe_5, reexamined in light of the INS results, indicate that the Ba-weighted modes dominate the low-temperature behavior of C_p.
Additional Information
© 2015 IOP Publishing Ltd. Received 3 August 2015, revised 2 October 2015. Accepted for publication 21 October 2015. Published 16 November 2015. The authors thank Petra Scheppan, Renate Hempel-Weber and members of the Kompetenzgruppe Struktur for providing experimental support. C.C. acknowledges the financial support of the CNRS-MPG program. M B and Yu G gratefully acknowledge financial support by the Deutsche Forschungsgemeinschaft (SPP 1415, 'Kristalline Nichtgleichgewichtsphasen (KNG)—Präparation, Charakterisierung und in situ-Untersuchung der Bildungsmechanismen').Additional details
- Alternative title
- Inelastic neutron scattering study of the lattice dynamics in the clathrate compound BaGe5
- Eprint ID
- 63316
- DOI
- 10.1088/0953-8984/27/48/485401
- Resolver ID
- CaltechAUTHORS:20160104-085808675
- Centre National de la Recherche Scientifique (CNRS)
- Max-Planck-Gesellschaft
- SPP 1415
- Deutsche Forschungsgemeinschaft (DFG)
- Created
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2016-01-04Created from EPrint's datestamp field
- Updated
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2022-07-12Created from EPrint's last_modified field