Determination of the Structural Parameters of an Incommensurate Phase from First Principles: The Case of Sc-II
2009 (English)In: Physical Review Letters, ISSN 0031-9007, Vol. 102, no 8, 085701- p.Article in journal (Refereed) Published
We propose a procedure to accurately describe the structural parameters of an incommensurate phase using ab initio methods by approximating it with a set of analogous commensurate supercells. We apply this approach to obtain the structural parameters of the Sc-II phase, which has recently been identified as a complex incommensurate structure similar to Sr-V. The calculated incommensurate ratio gamma, lattice parameters, and Wyckoff positions of Sc-II are in excellent agreement with the available experimental data. Our results show that gamma increases with pressure up to 60 GPa approaching but never reaching the commensurate value 4/3. Hence calculations do not confirm the prediction made based on the reanalyzing of experimental data. When pressure exceeds 70 GPa, gamma shows a sharp decrease that might be considered as the precursor of a new structural phase transition.
Place, publisher, year, edition, pages
2009. Vol. 102, no 8, 085701- p.
IdentifiersURN: urn:nbn:se:uu:diva-129897DOI: 10.1103/PhysRevLett.102.085701ISI: 000263816200032OAI: oai:DiVA.org:uu-129897DiVA: diva2:345578