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A transverse Peierls transition can occur when transverse acoustic phonons couple with conducting p-orbital electrons. Here, the authors observe an incommensurate transverse Peierls transition and signatures of a chiral charge density wave in EuAl₄.

A common feature of many transition metal materials is global symmetry breaking at low temperatures. Here the authors show that such materials are characterized by fluctuating symmetry-lowering distortions that exist pre-formed in higher temperature phases with greater average symmetry.

Using a combined computational-experimental approach, the authors determine that the long-observed anomalous hardness of the tantalum carbides can be attributed to a loss of dislocation plasticity on {111} planes at lower carbon contents.

Energy gaps can be induced by spatial modulation of the electronic potential. Here, the authors demonstrate a large and robust energy gap in a free-standing carbon nanotube utilizing a 15-gate keyboard that spatially modulates the local potential.

Optical excitation is a way to control phase transitions in materials, but it lacks spatial specificity. Now, valley-selective photodoping in a Peierls insulator is demonstrated as a method to optically engineer phase textures with minimal heating.

The still-developing understanding of topologically non-trivial phases of matter has led to new mechanisms for unconventional many-body behaviour. Here the authors present a model where the symmetry needed for a symmetry-protected topological phase only emerges after the formation of long-range order.

Recent studies have recognized that plasticity in metals can be controlled by dislocation avalanches. Here the authors examine temperature-dependent microplasticity in bcc Nb and reveal the dominance of athermal screw dislocation activity during intermittent slip.

One-dimensional metals are predicted to exhibit charge-order fluctuations and become insulators at low temperature. Experiments on silicide nanowires grown on silicon reveal that fluctuations in the narrowest wires determine the electronic properties, and can be exploited in nanoelectronic devices.

Electron diffraction is used to show that the melting of crystalline bismuth after laser excitation occurs exceptionally fast, within half the period of a lattice vibration. The extraordinary fast melting is attributed to profound laser-induced changes in the potential energy surface of the bismuth lattice: in the changed potential, the atoms experience strong driving forces that launch them from their initial equilibrium positions and towards the disorder typical of liquids.

A single layer of graphene on top of a hexagonal boron-nitride sheet can stretch to form a commensurate structure, or not — depending on the rotation angle between the two layers. In the case of commensurability, strain gets concentrated in domain walls, resulting in soliton-like structures.

The formation of defects in numerous systems is believed to follow universal scaling laws arising from the Kibble–Zurek mechanism. Ulm et al.measure this scaling law for defects created in ion Coulomb crystals, confirming the predicted behaviour for a system of 16 ions.

The mechanism of the charge density wave in kagome metals is under intense debate. Here, by using a combination of diffuse scattering and inelastic x-ray scattering, the authors show that the charge density wave transition in (Cs,Rb)V₃Sb₅ is of the order-disorder type.

The authors report the discovery of charge order with onset temperature of 800 K in the kagome superconductor YRu₃Si₂. In addition, they observe time-reversal symmetry breaking below 25 K, field-induced magnetism below 90 K and bulk multi-gap superconductivity below 3.4 K.

Group IV–VI materials often exist in a state near an electronic or structural phase transition. Here, the authors use ultrafast X-ray scattering to show that coupling of band-edge electrons and phonons causes the ferroelectric instability observed in lead telluride.

Metallization of pure hydrogen via overlapping of electronic bands requires high pressure above 3 Mbar. Here the authors study the Ba-H system and discover a unique superhydride BaH₁₂ that contains molecular hydrogen, which demonstrates metallic properties and superconductivity below 1.5 Mbar.

Skyrmions, when driven by any applied force, experience an addition sideways motion known as the skyrmion hall effect. Here, Brearton et al. present a reciprocal space method for determining the strength of the skyrmion hall effect, making measurement possible for skyrmion lattices.

Dense nanostructuring of hBN-encapsulated graphene enables band structure engineering with distinct magnetotransport signatures and a tunable bandgap.

Synthetic oligo-/polyynes with unprecedented length are used to model the elusive carbon allotrope carbyne. Spectroscopic and physical analyses show that endgroups influence the properties of shorter derivatives, but these effects predictably diminish in longer molecules. Molecular symmetry documents the evolution of characteristics from oligoynes to polyynes and offers predictions for the D_∞h structure of carbyne.

The development of future computation devices will be aided by a better understanding of the physics underlying material behaviors. Using thermoreflectance and spatially resolved X-ray microscopy, Kumar et al. elucidate the origin of two types of negative differential resistance in NbO₂ memristors.

The interplay between superconductivity, electron correlation and atomic ordering is at the heart of condensed-matter physics. Here, the authors demonstrate a link between superconductivity in the layered chalcogenide TaS_2−xSe_xand the ordering of the sulphur and selenium atoms

The Kibble–Zurek mechanism describes the formation of topological defects in systems undergoing continuous phase transitions, and predicts a power law for their density. Pyka et al. create defects in ion coulomb crystals and observe their scaling behaviour in the context of the Kibble–Zurek theory.

Controllable dislocations are desirable for modulating the physicochemical properties of materials. Here authors present a light-driven strategy for reversible high-density dislocation writing in ferroelectric crystals, enabling multidimensional manipulation and repeatable erasure, with potential for innovating informatics and functional materials.

Machine-learned potentials are accurate but often lack broad applicability. Here, authors develop a general-purpose neuroevolution potential for 16 metals and their alloys, achieving efficient and accurate predictions of various physical properties.

The Tomonaga–Luttinger liquid model is the leading candidate for describing one-dimensional metallic conductors at low temperature. Yet, experimental evidence that it is valid is sketchy. Scanning tunnelling and photoemission spectra suggest that it does, in fact, describe the behaviour of chains of gold atoms self-assembled on the surface of germanium.

An ultrabright femtosecond electron source is used to monitor the molecular motions in the organic salt (EDO-TTF)₂PF₆ as it undergoes its photo-induced insulator-to-metal phase transition.

Ultrafast excitation offers new routes to controlling material properties on short timescales, but probes are needed to better understand the changes. By studying the phonon spectrum of VO₂ in the time domain, Wall et al. find a prompt change in lattice potential after a photoinduced structural transition.

A charge-density wave state was recently reported in the bilayer kagome metal ScV₆Sn₆, but its nature is debated. Here, using inelastic X-ray scattering, the authors observe two competing charge-density waves and find the ground state is promoted by a momentum-dependent electron-phonon interaction.

Nematicity, the spontaneous breaking of lattice rotational symmetry, plays an important role in kagome metals. Here, the authors report on a nematic phase within seven Kelvin below the charge density wave transition in the bilayer kagome metal ScV₆Sn₆.

Experimental evidence of coherent charge transport in the normal state of the kagome metal CsV₃Sb₅ is presented, revealing the nature of correlated order in kagome metals and new directions for exploring quantum coherence in correlated electron systems.