Вид документа : Статья из журнала Шифр издания : 54/S 53 Автор(ы) : Shein I. R., Ivanovskii A. L. Заглавие : First-principles calculations of elastic and electronic properties of tetragonal Th2NiC2 as a parent phase for new superconductors Место публикации : Journal of Alloys and Compounds. - 2013. - Vol. 551. - С. 338-342: il. Примечания : Bibliogr. : p. 341-342 (36 ref.) ISSN: 0925-8388 ББК : 54 Предметные рубрики: ХИМИЧЕСКИЕ НАУКИ Ключевые слова (''Своб.индексиров.''): th2nic2--elastic properties--ab initio calculations--inter-atomic bonding--electronic properties Аннотация: This work reports on the elastic, electronic properties and inter-atomic bonding of the newly discovered superconductor Th2NiC2 as obtained within ab initio calculations. We found that Th2NiC2 is mechanically stable and it will behave as a ductile material exhibiting enhanced elastic anisotropy in shear and a rather low hardness. The inter-atomic bonding in Th2NiC2 is described as an anisotropic mixture of covalent and ionic contributions, where inside [Th2C2] blocks covalent Th–C bonds emerge, and these blocks are bonded with the Ni atomic sheets through directional Ni–C bonds. Additionally, some inter-atomic ionic Th–C interactions occur owing to charge transfer Th → C. Our data reveal that for Th2NiC2 the Fermi level is located in a deep DOS minimum and the experimentally observed increase in TC in the sequence Th2NiC2 → Th1.8Sc0.2NiC2 may be explained by the growth of N(EF). We also speculate that an increase in N(EF) (and, probably, in TC) for Th2NiC2-based materials may be also achieved by an alternative way: by electron doping – for example, by partial substitution of V for Th or Cu for Ni, as well as by partial substitution of N for C with the formation of Th–Ni carbonitrides like Th2NiC2−xNx Доп.точки доступа: Ivanovskii, A. L.