Incommensurate atomic density waves in the high-pressure IVb phase of barium
| Autor: | Elena Bykova, Phil Pattison, Gervais Chapuis, Alla Arakcheeva, Leonid Dubrovinsky, Maxim Bykov, Vladimir Dmitriev |
|---|---|
| Přispěvatelé: | Ecole Polytech Fed Lausanne, Lab Phys Matiere Complexe, CH-1015 Lausanne, Switzerland, Phase Solut Co Ltd, Ch Mesanges 7, CH-1012 Lausanne, Switzerland, Univ Bayreuth, Inst Expt Geochem & Geophys BGI, D-95440 Bayreuth, Germany, Ecole Polytech Fed Lausanne, IPSB, Lab Cristallog, CH-1015 Lausanne, Switzerland, European Synchrotron Radiation Facility (ESRF) |
| Rok vydání: | 2017 |
| Předmět: |
Ba IVb
Diffraction Synchrotron radiation chemistry.chemical_element 02 engineering and technology incommensurately modulated structures host–guest structures 01 natural sciences Biochemistry Interpretation (model theory) Density wave theory atomic density waves Phase (matter) 0103 physical sciences General Materials Science 010306 general physics Atomic density [PHYS]Physics [physics] Crystallography Chemistry Barium General Chemistry host-guest structures 021001 nanoscience & nanotechnology Condensed Matter Physics Research Papers QD901-999 Chemical physics High pressure high-pressure barium phases 0210 nano-technology |
| Zdroj: | International Union of Crystallography journal International Union of Crystallography journal, International Union of Crystallography 2017, 4, pp.152-157. ⟨10.1107/S2052252517000264⟩ 'IUCrJ ', vol: 4, pages: 152-157 (2017) IUCrJ IUCrJ, Vol 4, Iss 2, Pp 152-157 (2017) |
| ISSN: | 2052-2525 |
| Popis: | Using single-crystal synchrotron radiation X-ray experiments, the host–guest structure of the Ba IVb high-pressure phase has been solved for the first time. The proposed systematic analysis of possible host–guest structure models shows that the structure belongs to the incommensurately modulated type. This model reveals an atomic density wave and its pressure-dependent evolution between 16.5 and 19.6 GPa. The host–guest structures of elements at high pressure discovered a decade ago still leave many open questions due to the lack of precise models based on full exploitation of the diffraction data. This concerns in particular Ba IV, which is stable in the range 12–45 GPa. With the example of phase Ba IVb, which is characterized here for the first time, a systematic analysis is presented of possible host–guest structure models based on high-quality single-crystal diffraction data obtained with synchrotron radiation at six different pressures between 16.5 and 19.6 GPa. It is shown that a new incommensurately modulated (IM) structure model better fits the experimental data. Unlike the composite models which are commonly reported for the Ba IV phases, the IM model reveals a density wave and its pressure-dependent evolution. The crucial role played by the selected model in the interpretation of structure evolution under pressure is discussed. The findings give a new experimental basis for a better understanding of the nature of host–guest structures. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|