dc.creator | Gou, Weiping | |
dc.creator | Rodriguez, Sergio Y. | |
dc.creator | Li, Yang | |
dc.creator | Ross, Joseph H. Jr. | |
dc.date.accessioned | 2016-01-12T00:16:46Z | |
dc.date.available | 2016-01-12T00:16:46Z | |
dc.date.issued | 2009 | |
dc.identifier.citation | Phys. Rev. B 80, 144108 (2009) | en |
dc.identifier.uri | https://hdl.handle.net/1969.1/156019 | |
dc.description.abstract | We describe A27l NMR experiments on Ba8AlxGe46−x type-I clathrates coupled with ab initio computational studies. For x=16, calculated spectra determined by the ab initio results gave good agreement with the measurements, with best-fitting configurations also corresponding to the computed lowest-energy atomic arrangements. Analysis of the NMR results showed that a distribution of Knight shifts dominates the central portion of the line. Computational results demonstrate that this stems from the large variation of carrier density on different sites. Al-deficient samples with x=12 and 13 exhibited a split central NMR peak, signaling two main local environments for Al ions, which we connected to the presence of vacancies. Modeling of the wide-line spectrum for x=12 indicates a configuration with more Al on the 24k site than for x=16. The results indicate the importance of nonbonding hybrids adjacent to the vacancies in the electronic structure near EF. We also address the static distortions from Pm3¯n symmetry in these structures. | en |
dc.language.iso | en_US | |
dc.publisher | American Physical Society | |
dc.title | NMR experiments and electronic structure calculations in Type-I BaAlGe clathrates | en |
dc.type | Article | en |
local.department | Physics and Astronomy | en |
dc.identifier.doi | 10.1103/PhysRevB.80.144108 | |