Insights into the structural complexity and local disorder of crystalline AsTe from semi-automated first-principles modelling.

A semi-automated workflow relying on atomic-scale modelling is introduced to explore and understand the yet-unsolved structure of the crystalline AsTe material, recently obtained from crystallization of the parent AsTe glass, which shows promising properties for thermoelectric applications. The seemingly complex crystal structure of AsTe is investigated with density functional theory, from the stand point of As/Te disorder, in a structural template derived from elemental-Te (Te), following experimental findings from combined X-ray total scattering and diffraction. Our workflow includes a combinatorial structure generation step followed by successive structure selection and relaxation steps with progressively-increasing accuracy levels and a multi-criterion evaluation procedure.

Metavalent Bonding in Crystalline Solids: How Does It Collapse?

The chemical bond is one of the most powerful, yet much debated concepts in chemistry, explaining property trends in solids. Recently, a novel type of chemical bonding was identified in several higher chalcogenides, characterized by a unique property portfolio, unconventional bond breaking, and sharing of about one electron between adjacent atoms. This metavalent bond is a fundamental type of bonding in solids, besides covalent, ionic, and metallic bonding, raising the pertinent question as to whether there is a well-defined transition between metavalent and covalent bonds.

Te NMR for structural investigations in phase change materials: Optimization of experimental conditions coupled to NMR shift prediction.

Phase Change Materials as those of the Ge-Sb-Te ternary system are of great interest for technological applications. Properties of these compounds are strongly related to presence of vacancies and structural investigations remain challenging. In this paper we evidence that Te NMR in natural abundance and using commercial systems at intermediate field (14.

Short range order and network connectivity in amorphous AsTe: a first principles, machine learning, and XRD study.

The atomic scale structure of amorphous AsTe is investigated through X-ray diffraction, first-principles molecular dynamics (FPMD), and machine learning interatomic potentials (ML-GAP) obtained by exploiting the ab initio data. We obtain good agreement between the measured and modelled diffraction patterns. Our FPMD results show that As and Te obey the 8-N rule with average coordination numbers of 3 and 2, respectively.

Ultra-Thin Platinum Deposits by Surface-Limited Redox Replacement of Tellurium.

Platinum is the most employed electrocatalyst for the reactions taking place in energy converters, such as the oxygen reduction reaction in proton exchange membrane fuel cells, despite being a very low abundant element in the earth's crust and thus extremely expensive. The search for more active electrocatalysts with ultra-low Pt loading is thus a very active field of investigation. Here, surface-limited redox replacement (SLRR) that utilizes the monolayer-limited nature of underpotential deposition (UPD) was used to prepare ultrathin deposits of Pt, using Te as sacrificial metal.