NMR and computational study of Ba8CuxGe46-x clathrate semiconductors

JOURNAL OF ALLOYS AND COMPOUNDS

卷:593

Article

Chen, Jing-Han¹  Arvij, Ali Sirusi¹  Zheng, Xiang¹  Rodriguez, Sergio Y.¹  Ross, Joseph H., Jr.¹ 

[1] Texas A&M Univ, Dept Phys & Astron, College Stn, TX 77843 USA

关键词: Clathrates;    NMR in condensed matter;    Band structure of semiconductors;   

DOI  :  10.1016/j.jallcom.2014.01.034

来源: Elsevier

【 摘 要 】

Ba8CuxGe46-x is a type-I clathrate material that forms as a semiconductor in a narrow composition range corresponding to the electron-balanced Zintl composition, with x = 5.3. We use NMR spectroscopy combined with ab initio electronic structure calculations to probe the electronic and structural behavior of these materials. Computational results based on a superstructure model for the atomic configuration of the alloy provide good agreement with the electric quadrupole-broadened NMR lineshapes. Modeling using the modified Becke-Johnson (TB-mBJ) exchange potential is also shown to agree well with experimental NMR Knight shifts. The results indicate that the Cu-Ge balance is the main factor determining the carrier density, within a narrow stability range near the ideal Zintl composition. (C) 2014 Elsevier B.V. All rights reserved.

【 授权许可】

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