An incommensurately modulated structure of eta '-phase of Cu.sub.3+x./sub.Si determined by quantitative electron diffraction tomography

0365488 - FZÚ 2012 RIV US eng J - Journal Article
Palatinus, Lukáš - Klementová, Mariana - Dřínek, Vladislav - Jarošová, Markéta - Petříček, Václav
An incommensurately modulated structure of eta '-phase of Cu_3+xSi determined by quantitative electron diffraction tomography.
Inorganic Chemistry. Roč. 50, č. 8 (2011), s. 3743-3751. ISSN 0020-1669. E-ISSN 1520-510X
R&D Projects: GA ČR GA203/09/1088
Grant - others:AV ČR(CZ) AP0701
Program: Akademická prémie - Praemium Academiae
Institutional research plan: CEZ:AV0Z10100521; CEZ:AV0Z40720504
Keywords : copper silicide * incommensurate structure * electron diffraction tomography * ab inition structure solution * superspace
Subject RIV: BM - Solid Matter Physics ; Magnetism
Impact factor: 4.601, year: 2011

The diffraction data of eta´-Cu(3+x)(Si,Ge) were collected by 3D quantitative electron diffraction tomography on a submicrometer-sized sample, and the structure was solved by the charge-flipping algorithm in superspace. The modulation functions of some atoms are very complicated and reach amplitudes comparable with the unit cell dimensions. The modulated structure can be described as sheets of Cu clusters separated by honeycomb layers of mixed Si/Ge positions. The shape of the Cu clusters in the sheets strongly varies with the modulation phase, and the predominant form is an icosahedron. The striving of the Cu layers to form icosahedral clusters is deemed to be the main driving force of the modulation. The combination of methods used in this work can be applied to other structures that are difficult to crystallize in large crystals and opens new perspectives, especially for investigations of aperiodic or otherwise complex metallic alloys.
Permanent Link: http://hdl.handle.net/11104/0006597