Volume 23 Issue 4, April 2024

Better control over the quality of materials dissipates doubts about charge order in infinite-layer nickelates and indicates that a previously observed superstructure is probably a spurious effect related to other crystalline phases. This finding strengthens the similarities between nickelates and cuprates.

Polaritonic losses, a root impediment to the many bounties of nanophotonics, may be evaded by resorting to the mathematics of synthetic frequencies offering ‘virtual’ gain.

Single spin defects are identified in gallium nitride at room temperature, exhibiting a spin readout contrast of up to 30%.

Highly efficient matrix-free hyperfluorescent organic light-emitting diodes are constructed with remarkably supressed Dexter transfer utilizing narrowband blue emitters encapsulated with hopped alkyl chains.

Restricting the directional segregation of mobile ions via strategic local ion confinement allows remarkable thermoelectric performance with better stability.

Light-driven artificial goosebumps enable the simple yet precise actuation of microstructures.

Pentagonal polyhedral oligomeric silsesquioxane (POSS)-based giant atoms self-assemble into Frank–Kasper phases that have not been previously observed in soft-matter systems.

Single-crystal black phosphorus nanoribbons have been grown through chemical vapour transport, using black phosphorus nanoparticles as seeds. The nanoribbons orient exclusively along the zigzag direction and have good semiconductor properties that render them suitable for use as channel material in field-effect transistors.

Non-layered transition metal carbides (TMCs) and layered transition metal dichalcogenides (TMDs) can form various heterostructure configurations through chemical conversion. This Review highlights the progress in the fabrication and control of TMC/TMD heterostructures and the exotic properties arising from these interfaces.

Single-crystal black phosphorus nanoribbons are grown uniformly on insulating substrates by chemical vapour transport growth with black phosphorus nanoparticles as seeds, demonstrating potential for application in nanoelectronic devices and the exploration of the exotic physics in black phosphorus.

The authors study spin transport anisotropy in a 5.5 nm black phosphorus ribbon encapsulated by boron nitride.

Samples of NdNiO_2+x are prepared with meticulous control of the oxygen content. Their X-ray scattering and spectroscopy measurements then reveal that the previously reported charge density wave in undoped infinite-layer nickelates is, in fact, a spurious effect.

An orbitally ordered state in Bi₂Sr₂CaCu₂O_8+x is revealed, which splits the energy levels of oxygen orbitals by ~50 meV.

Exploiting optical multimodal confinement, the deep-subwavelength confinement of hyperbolic phonon polaritons is demonstrated in isotopically pure hexagonal boron nitride, enabling nanoscale polariton manipulation.

Propagation losses have limited the practical use of polaritons in photonic applications. Here the authors demonstrate a substantial enhancement in the propagation distance of phonon polaritons, employing synthetic optical excitation of complex frequency with virtual gain synthesized by combining multiple real frequency measurements.

Optically detected magnetic resonance (ODMR) is an efficient mechanism for quantum sensors and has been discovered in a few systems, but all have technological limitations. Here the authors report room temperature ODMR in single defects in GaN, promising for integrated quantum sensing applications.

Suppressed Dexter transfer is needed to achieve efficient and stable hyperfluorescence, but complex matrices must be involved. A molecular design strategy has been proposed where Dexter transfer can be substantially reduced by an encapsulated terminal emitter, leading to ‘matrix-free’ hyperfluorescence.

Cu₂Se is of interest for thermoelectrics as it is environmentally sustainable and has a high figure of merit ZT; however, copper ion migration impacts device stability. Here a co-doping strategy that combines steric and electrostatic effects is shown to improve device stability as well as improving ZT to 3.

Oxides with a face-centred cubic anion sublattice are generally not considered as solid-state electrolytes. Li superionic conductivity in face-centred cubic oxides with face-sharing Li configurations have now been created through cation over-stoichiometry in rocksalt-type lattices via excess Li.

Although silicon anodes are promising for solid-state batteries, they still suffer from poor electrochemical performance. Chemo-mechanical failure mechanisms of composite Si|Li₆PS₅Cl and solid-electrolyte-free silicon anodes are now revealed and should help in designing improved electrodes.

Developing active and stable atomically dispersed catalysts is challenging because of weak non-specific interactions between catalytically active metal atoms and supports. A general method for synthesizing these catalysts via photochemical defect tuning for controlling oxygen-vacancy dynamics is proposed.

Light-induced artificial goosebumps on liquid crystal elastomer skin are used to precisely manipulate passive microstructures, achieving a localized and controllable system for programmable micromachines.

Soft building blocks tend to be near spherical, limiting their packing structures to those found in metallic systems. Here the authors report the spontaneous generation of highly deformed mesoatoms using molecular pentagons and observe Frank–Kasper phases not found in metal alloys.