Developments in the structural science of materials

Abstract

The papers published during the last year in IUCrJ in the fields of materials and computational science illustrate well the challenges posed by structural problems in the science of materials and the key role that computation can play in this and related fields in structural science. As in previous years, they demonstrate the continuing developments in techniques and instrumentation and the increasingly complex structural problems which these developments now make accessible; the role of computation in interpreting and predicting structures is equally clear.An excellent example of technical developments facilitating new structural science is provided by the article of Meng & Zuo (2016), which probes three-dimensional nanostructures using a technique that employs high-resolution and low-dose scanning electron nano-diffraction (SEND) to acquire three-dimensional diffraction patterns. Their work investigates TiN -a material that is widely used in the electronics industry -and Fig. 1 illustrates how they were able to reconstruct grain structures within the material. Detailed knowledge of this microstructure is essential in understanding and optimizing the properties of the material Previous editorials have emphasized the key role of diffuse scattering, which is also facilitated by technical advances. The importance of the field in materials science is well illustrated by the article of Sawa (2016), which highlights the work of Welberry & Goossens (2016) on the interpretation of diffuse scattering from the high-temperature superconductor, HgBa 2 CuO 4 + . Analysis of the diffuse scattering data reveals fascinating features involving the displacement of metal atoms around oxygen interstitial chains. This article along with several others demonstrates the need to elucidate complex structural features in disordered materials.Analysis of diffuse scattering is also vital in the particularly exciting challenge of developing detailed models for the atomic arrangements in quasicrystals. The article of Ishimasa (2016) highlights the study of Yamada et al. (2016) on the atomic structure and phason modes of the Sc-Zn icosahedral quasicrystal, which employs synchrotron-based diffraction and diffuse scattering to investigate this difficult problem.The complexity of structural problem that can now be addressed is well illustrated in the paper of Rozhdestvenskaya et al. (2017), who use a wide range of techniques including several electron crystallographic methods, XRPD and modelling to solve the structure of denisovite, a highly complex, fibrous, polytypical silicate. The structure revealed is shown in Fig. 2. The article is an elegant illustration of the capacity of, and the need for, a multi-technique approach in addressing structural problems in materials science, A further example of complex structural science is given by the study of SnTe reported by Sist et al. (2016). This material is increasingly investigated owing to its potential as a thermoelectric material and as a topological insulator. Their study again reveals the im...