New Structure

Suppressing Atomic Diffusion with the Schwarz Crystal Structure in Supersaturated Al–Mg Alloys

Because of the nature of interatomic bonding, atomic diffusivity is notably higher in metals relative to that in ceramics and compounds with covalent or ionic bonds. This feature enables substantial tuneability of structures at various length scales by tailoring the diffusion controlled processes during the synthesis and subsequent treatments, resulting in a broad spectrum of properties and performance in metallic materials, but this causes their customized properties to be unstable at elevated temperatures.

Discovery of Segmented Fermi Surface in a Superconductor

Superconductivity is a long-standing research topic in physics. Superconductors have critical applications because of their unique properties like zero resistance and complete diamagnetism. When a superconductor is in the superconducting state, an energy gap will form at the Fermi level, so there is no Fermi surface in a superconductor. In 1965, theoretical physicists predicted that when the Cooper pair momentum in a superconductor is large enough, quasiparticles will be generated in the superconducting energy gap, thus forming a segmented Fermi surface. However, this prediction has not been confirmed experimentally for more than 50 years because when the Cooper pair momentum of conventional superconductors is large enough to create quasiparticles, the Cooper pair itself will break up and lose superconductivity.

A New Metastable Solid Structure-Schwarz Crystal

Metals usually exist in the form of polycrystals with a large number of crystal interfaces. However, the stability of polycrystals is much lower than that of perfect crystals (single crystals) due to the relative high energy of disordered atomic arrangement in grain boundary region.

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