English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

A detailed account of the local atomic structure and disorder at 5~K acrossthe phase diagram of the high temperature superconductorK$_x$Fe$_{2-y}$Se$_{2-z}$S$_z$ $(0 \leq z \leq 2)$ is obtained from neutrontotal scattering and associated atomic pair distribution function (PDF)approaches. Various model independent and model dependent aspects of theanalysis reveal a high level of structural complexity on the nanometerlength-scale. Evidence is found for considerable disorder in the $c$-axisstacking of the FeSe$_{1-x}$S$_{x}$ slabs without observable signs ofturbostratic character of the disorder. In contrast to the related FeCh (Ch =S, Se) type superconductors, substantial Fe-vacancies are present inK$_x$Fe$_{2-y}$Se$_{2-z}$S$_z$, deemed detrimental for superconductivity whenordered. Our study suggests that the distribution of vacancies significantlymodifies the iron-chalcogen bond-length distribution, in agreement withobserved evolution of the PDF signal. A crossover like transition is observedat a composition of $z\approx1$, from a predominantly vacancy-disordered stateat the selenium end to a more vacancy-ordered (VO) phase closer to the sulfurend of the phase diagram. The S-content dependent measures of the localstructure are found to exhibit distinct behavior on either side of thiscrossover, correlating well with the evolution of the superconducting state tothat of a magnetic semiconductor towards the $z\approx2$ end. The behaviorreinforces the idea of the intimate relationship of correlated Fe-vacanciesorder in the local structure and the emergent electronic properties.

Correlated disorder to order crossover in the local structure of K$_x$Fe$_{2-y}$Se$_{2-z}$S$_z$