The Superstructure of Semiconducting SmTe2−x

✍ Scribed by Seon-Mi Park; So-Jeong Park; Sung-Jin Kim

• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 286 KB
• Volume: 140
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1998.7891

✦ Synopsis

SmTe 1.84 was synthesized and the crystal structure was studied by the single-crystal technique. The substructure was isostructural with LaTe 2؊x , where corrugated rock salt LaTe slabs alternate with planar tellurium square lattices. The substructure of SmTe 1.84 is tetragonal anti-Cu 2 Sb type and the superstructure is (5؋(5 of the tetragonal subcell. The superstructure is tetragonal, with P4 2 /n symmetry, a ‫؍‬ 9.709(1) A s and c ‫؍‬ 18.007(7) A s . There are both ordered and disordered defects in the Te sheet. The superstructure obtained consists of the three possible stable solutions suggested by Lee and Foran, and all three solutions were found in a single crystal. The resistivity dependence on temperature indicates that SmTe 1.84 is semiconducting, which seems due to structural modulation. The structural stability of the other phases of SmTe n (n ‫؍‬ 1-2) is discussed in terms of temperature and ionic radius ratio.