Optimized Synthesis of the Bismuth Subiodides BimI4 (m = 4, 14, 16, 18) and the Electronic Properties of Bi14I4 and Bi18I4

• Published in: European journal of inorganic chemistry Vol. 2017; no. 47; pp. 5609 - 5615
• Main Authors: Weiz, Alexander, Anh, Mai Lê, Kaiser, Martin, Rasche, Bertold, Herrmannsdörfer, Thomas, Doert, Thomas, Ruck, Michael
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 22.12.2017
• Subjects: Bismuth; Chain structures; Conducting materials; Crystal structure; Crystals; Electron states; Inorganic chemistry; Iodides; Layered materials; Magnetoresistance; Magnetoresistivity; Polycrystals; Ribbons; Single crystals; Spin-orbit interactions; Subvalent compounds; Tapes (metallic)
• ISSN: 1434-1948; 1099-0682
• DOI: 10.1002/ejic.201700999

We optimized the syntheses of α‐ and β‐Bi4I4 and transferred the method to the very bismuth‐rich iodides Bi14I4, Bi16I4, and Bi18I4. Phase‐pure, microcrystalline powders of BimI4 (m = 4, 14, 18) can now by synthesized on a multigram scale. Conditions for the growth of single crystals of Bi16I4 and Bi18I4 were determined. The redetermination of the crystal structure of Bi16I4 hints at a stacking disorder or the presence of 1∞[BimI4] ribbons with m = 14 and 18 among the dominant type along with m = 16. The electronic band structures for m = 14, 16, and 18 were calculated including spin‐orbit coupling. They vary markedly with m and show numerous bands crossing the Fermi level, predicting a 3D‐metallic behavior. Measurements of the electrical resistivity of a polycrystalline sample of Bi14I4 as well as polycrystalline and single‐crystalline samples of Bi18I4 confirmed their metallic nature over the temperature range 300 K to 2 K. For Bi18I4, a positive and strictly linear magnetoresistance at 2 K in static magnetic fields up to 14 T was observed, which could indicate a topologically nontrivial electronic state. Phase‐pure powders and single‐crystals of bismuth‐rich iodides BimI4 (m = 4, 14, 16, 18) were synthesized. The crystal structure of Bi16I4 is reinvestigated and new real‐structure models are developed. Measurements reveal metallic conductivity and linear magnetoresistance for Bi18I4. The latter indicates topologically nontrivial states in the bismuth‐rich iodides.