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Copper position in type-I Ba8Cu4Si42 clathrate |
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| Authors: | L. Yang T. Liu B.X. Li S.Y. Chen P. Shen Y.W. Wang |
| Affiliation: | a Laboratory of New-Structured Materials, Department of Materials Science and Engineering, Zhejiang University, Zheda road 38, Hangzhou 310027, PR China b Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, PR China c Department of Physics, Hangzhou Teacher College, Hangzhou 310012, PR China d Department of Chemistry, Building 207, Technical University of Denmark, DK-2800 Lyngby, Denmark e Department of Mechanical Engineering, I-Shou University, Kaohsiung, Taiwan, ROC f Institute of Materials Science and Engineering, National Sun-Yat-sen University, Kaohsiung, Taiwan, ROC |
| Abstract: | Local structure of Cu in a type-I Ba8Cu4Si42 clathrate has been investigated by synchrotron X-ray powder diffraction, Cu K-edge extended X-ray absorption fine spectroscopy, X-ray absorption near edge spectroscopy (XANES) and theoretical calculation. It is found that XANES spectra cannot be explained by the substitution of Cu atoms at Si16i, and Si24k positions. Our calculations show that the binding energies of the Si atom in Si16i, Si24k and Si6c positions are 9.000, 9.495 and 8.911 eV, respectively. Both experimental and theoretical results support that Cu atoms in the type-I Ba8Cu4Si42 clathrate, as a doped element, prefer to occupy the least-binding Si, i.e., the Si6c sites. No structural change between 112 and 300 K was observed and the (100)-faceted cubic crystal has negligible distortion/ordering according to transmission electron microscopy. |
| Keywords: | 82.75.Fq 81.05.Zx 61.72.Tt 61.10.Ht |
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