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Title: Anharmonic lattice dynamics in type-I clathrates from first-principles calculations

Journal Article · · Physical Review. B, Condensed Matter and Materials Physics
DOI:https://doi.org/10.1103/PHYSREVB.72.2· OSTI ID:20787752
;  [1]
  1. Department of Chemistry and Department of Physics, University of Aarhus, DK-8000 A rhus C (Denmark)

The anharmonic lattice dynamics of (Sr/Ba){sub 8}Ga{sub 16+x}Ge{sub 30-x} type-I clathrates are studied using first-principles calculations. The guest atoms in the large cages are found to lie in strongly anharmonic potentials, resulting in off-center (disordered) equilibrium positions for the Sr rattler. The lowest energy modes for Sr form a four level system with a tunneling splitting of only 0.04 meV. The thermodynamical properties and the inelastic neutron scattering spectra of the anharmonic rattlers are investigated.

OSTI ID:
20787752
Journal Information:
Physical Review. B, Condensed Matter and Materials Physics, Vol. 72, Issue 22; Other Information: DOI: 10.1103/PhysRevB.72.220301; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
Country of Publication:
United States
Language:
English