Volume 22 Issue 7, July 2023

The study of point defects in non-metallic crystals has become relevant for an increasing number of materials applications. Progress requires a foundation of consistent definitions and terminology. This Comment clarifies the underlying definitions of point defects, encourages the correct use of relative charge for their description and emphasizes their recognition as quasiparticles.

On the 10th anniversary of the Graphene Flagship, Nature Materials talks to Jari Kinaret, Professor of Physics at the Chalmers University of Technology and Director of the Graphene Flagship. We look back at the flagship’s challenges and achievements and discuss future graphene research and initiatives in Europe.

A bicontinuous conducting polymer hydrogel with high electrical conductivity, stretchability and fracture toughness in physiological environments achieves high-fidelity monitoring and effective stimulation of tissues and organs.

A safe, inhalable formulation of mucin-interacting hydrogel microparticles creates a dense protective network in the lungs against viral infections.

Controlling the twist angles between three α-phase molybdenum trioxide single layers enables the programmable and reconfigurable canalization of phonon polaritons along multiple in-plane directions.

A two-dimensional conjugated polymer is synthesized that demonstrates low electron effective masses and high mobility. These properties show that this material could act as a viable alternative to silicon-based semiconductors.

An ultra-microporous metal–organic framework glass foam shows outstanding gas sieving properties for challenging gas mixtures.

A two-dimensional atomically flat insulator with large dielectric constant and high breakdown field strength has been successfully grown. This material could serve as the dielectric and encapsulation layers for two-dimensional materials for studying their emergent physics, as well as for next-generation electronics.

The output mechanical energy densities of ferroelectric polymers remain orders of magnitude smaller than those of piezoelectric ceramics and crystals, limiting their applications in soft actuators. But polymer composites subject to an electro-thermally driven ferroelectric phase transition under low electric fields are now shown to have giant actuation strains and large energy densities.

High-quality aluminium nitride (AlN) heteroepitaxial films are obtained by the controlled discretization and coalescence of columns using nanopatterned AlN/sapphire templates with regular hexagonal holes. The density of dislocation etch pits in the AlN heteroepitaxial films is reduced to approximately 10⁴ cm^–2, approaching the value of that in AlN bulk single crystals.

RNA-based therapeutics hold promise for the treatment of several diseases. This Review provides an overview of hydrogels for RNA delivery, discussing how the chemical nature and physical properties of hydrogels can be explored for tailored RNA loading and release, and highlighting the use of these materials in biomedical applications.

Large-size single-crystal van der Waals layered Bi₂SeO₅ has been synthesized with a high dielectric constant and high breakdown field strength for two-dimensional electronics applications.

Employing an oxidation-activated charge transfer strategy to oxidize transition-metal dichalcogenides into transition-metal oxides, the authors imprint plasmonic cavities with laterally abrupt doping profiles and nanoscale precision demonstrating plasmonic whispering-gallery resonators.

The authors report subatomic precision in measuring the displacement of a nanowire. Such precision is achieved by employing deep-learning enabled analysis of single-shot scattering of topologically structured superoscillatory illumination.

Understanding lithium dynamics in solid-state electrolytes used for Li-ion batteries can be challenging. Using nonlinear extreme-ultraviolet spectroscopies, a direct spectral signature of surface lithium ions showing a distinct blueshift relative to the bulk absorption spectra is observed in a prototypical solid-state electrolyte.

High-quality AlN heteroepitaxial films are obtained by controllable discretization and coalescence of columns on nano-patterned AlN/sapphire templates with hexagonal holes, where the density of dislocation etch pits is greatly reduced to ~10 × 10⁴ cm⁻².

Employing terahertz nanoscopy, we image highly confined, in-plane anisotropic acoustic terahertz plasmon polaritons in monoclinic Ag₂Te platelets placed above a Au layer, verifying a linear dispersion and elliptical isofrequency contour in momentum space.

The direction of polariton canalization—its diffractionless propagation—in twisted bilayers at the magic angle is hindered by the lack of multiple magic angles. By controlling the twist angles between three α-MoO₃ layers, reconfigurable and spectrally robust polariton canalization along any in-plane direction is demonstrated.

Piezoelectric actuators play a critical role in precision positioning devices; however, materials with high actuation strain and mechanical energy density are rare. Here a composite of poly(vinylidene fluoride) and TiO₂ demonstrates superior performance in these metrics, with the ferroelectric transition driven by Joule heating.

Linear π-conjugated polymers have attracted great attention as semiconductors for (opto)electronic devices, but charge transfer is only effective along polymer chains. Here poly(benzimidazobenzophenanthroline)-ladder-type two-dimensional conjugated polymers are presented with high charge carrier mobilities.

Membranes formed from porous adsorbents can improve the economics of industrially difficult separations but require support materials that reduce gas permeance. Here an amorphous glassy foam membrane without a support is formed from ZIF-62 that shows high selectivity and permeance for CH₄/N₂ separations.

A bi-continuous hydrogel prepared from phase-separated PEDOT:PSS and polyurethane is 3D printed into soft biolelectronic devices with high electrical conductivity, stretchability and toughness for long-term in vivo electrophysiological monitoring and stimulation.

A bioadhesive hydrogel delivered via inhalation efficiently coats the airway and restricts SARS-CoV-2 virus variant penetration in mice and non-human primates

Microtubules respond to mechanical compression by deforming, becoming more stable, which results in CLASP2 recruitment to the distorted shaft—a process crucial for cell migration through confined spaces.