Excitonic quantum oscillations are observed in correlated electron–hole bilayers and quantum phase transitions are identified between excitonic insulator and bilayer quantum Hall states under strong magnetic fields.

Cotton yarns encapsulated by a gel layer show dynamic swelling in methanol, creating interfacial self-reinforcement and pressure modulation mechanisms that enable the fabrication of fibre-shaped methanol fuel cells.

Quantum oscillations are reported in Coulomb-coupled electron–hole double layers that originate from recurring transitions between competing excitonic insulator and layer-decoupled quantum Hall states.

Seeded growth methods are used to prepare highly ordered, crystalline semiconducting poly(di-n-hexylfluorene) platelet micelles, which exhibit long-range anisotropic exciton diffusion, particularly along the π–π-stacking direction.

By doping ice with NaCl, it is shown that a flexoelectric coefficient of up to 10 μC m⁻¹ is generated, enabling effective piezoelectric coefficients that are comparable to those of ceramics. This arises from the streaming current of quasi-liquid flow through grain boundaries from one side of the sample to the other.

An electron ptychography and energy-loss spectroscopy study of La₂PrNi₂O₇, a material that exhibits high-temperature superconductivity, is conducted.

The authors demonstrate deeply subwavelength light confinement in the terahertz spectral range by exploiting the strong light–matter coupling and hyperbolicity of phonon polaritons in hafnium-based dichalcogenides.

Insights to elucidate the composition–behaviour relationship in organic photovoltaic materials are required. Here the phase behaviour of disordered polymer:small-molecule acceptor blends is studied and an extended model is invoked to understand the temperature–composition diagrams.

Two-dimensional polyamide/lithiated Nafion interphase layers assembled into ultrathin sheets show high-rate, high-capacity Li plating/stripping as well as high energy and power densities, enabling the fabrication of high-performance anode-free Li metal batteries.

Using visible-light-induced crosslinking, a local stiffening approach is developed for ex vivo mouse and human lung tissue as an early lung injury model, directing epithelial cell mechanosensing, differentiation and nascent protein deposition.

Pioneer of high-pressure physics and superconductivity.

In this issue we present three papers on the topological properties or structure of ferroelectrics, which are interlinked.

Seven years on from updates to our data sharing policies, we reflect on data-deposition-related changes to our published papers and continue to strongly encourage authors to make source data openly available.

The Hall effect has been a powerful probe of the physics of materials for more than a century.

Identification of amorphous phases in nanoparticles by atomic-resolution transmission electron microscopy (TEM) requires analyses such as tilt-angle-dependent TEM imaging and single-nanoparticle electron diffraction, rather than relying on a single TEM image.

Budget cuts and shifting funding priorities will reduce opportunities for early-career researchers in the USA.