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Exploring lattice distortions from magnetic short-range ordering (SRO) facilitates the understanding of magnetic long-range ordering (LRO). Here the authors apply high-multipole nonlinear optical polarimetry to track SRO induced distortions in CrSiTe₃, showing that LRO is established via a crossover from two- to three-dimensional SRO.

The coexistence of frustrated magnetism and bond order is demonstrated in a family of antiferromagnets. Layers of dual frustrated orders are interleaved in the same crystal lattice, which presents an exciting possibility for engineering new responses.

5d transition metal iridates provide a platform to study the combined effects of strong spin orbit coupling and strong electronic correlations. Here, the authors find a quadratic band touching in the band structure of Pr₂Ir₂O₇, suggesting it may be tuned to form various strongly correlated topological phases.

Exploiting the magnetic field-induced shift of entropy in certain molecular salts when going from 1D short-range ordering to a 3D quantum critical point could provide a route for producing strongly fluctuating quantum materials.

Some materials can display magnetic order despite having spin-singlet ground state on individual magnetic sites. This arises due to exchange interactions mixing excited crystal electric field states. Here, Gao et al study and example of such a system, Ni₂Mo₃O₈, and find that crystal electric field states in both the paramagnetic and antiferromagnetic states exhibit dispersive excitations.

Oscillations of the order parameter amplitude in magnetically ordered materials provide condensed matter analogues of the Higgs boson but in most cases they are unstable. Dally et al. show that the quasi-one-dimensional magnet α-Na_0.9MnO₂ supports stable amplitude excitations.

A study reveals a temperature-dependent cascade of different symmetry-broken electronic states in the kagome superconductor CsV₃Sb₅, and highlights intriguing parallels between vanadium-based kagome metals and materials exhibiting similar electronic phases.

Coherent control and giant modulation of optical nonlinearity in a van der Waals layered magnetic insulator is demonstrated using Floquet engineering.

Local probing into the microscopic degrees of freedom is highly desired to understand emergent exotic quantum phases. Here, the authors report a canted ferromagnetic phase preceded by local point symmetry breaking at low temperature in Ba₂NaOsO₆, acquired by probing into the spin, orbital and lattice degrees of freedom.

In Weyl semimetals, unusual electronic transport phenomena are predicted to occur, such as an axial anomaly which violates the conservation of chiral fermions. Here, the authors evidence such behaviour via the occurrence of negative magnetoresistance in layered high-purity non-magnetic metals.

Breaking the time-reversal symmetry of the surface states of topological insulators is predicted to produce many exotic and potentially useful phenomena. Spin-resolved angle-resolved photoemission spectroscopy spectra reveal that magnetic dopants can induce such symmetry breaking in Be₂Se₃ thin films.

Tuning the electronic interactions by changing the dielectric environment of twisted bilayer graphene reveals the disappearance of the insulating states and their replacement by superconducting phases, suggesting a competition between the two phases.

The electronic properties of bismuth under an applied magnetic field have latterly become a topic of interest. An angle-resolved magnetostriction approach is now used to provide thermodynamic evidence for unusual symmetry-breaking effects.

In the conventional quantum Hall effect, a two-dimensional electronic system in the presence of a magnetic field forms metallic conduction paths at the edge of the sample. This paper experimentally demonstrates a sought-after three-dimensional and spontaneous version of this effect; the bulk of a Bi0.9Sb0.1 crystal is shown to be insulating, while two-dimensional metallic conduction paths exist at the surface, without any applied magnetic field.

Thermal transport measurements show that there is a thermal Hall effect in the out-of-plane direction in two cuprates in the pseudogap regime. This indicates that phonons are carrying the heat and that they have a handedness of unknown origin.

The so-called pseudogap phase in hole-doped cuprate superconductors is associated with an unusually large thermal Hall effect that attains unprecedented levels as the parent Mott insulator is approached.

Helical Dirac fermions are charge carriers that behave as massless relativistic particles with an intrinsic angular momentum (spin) locked to their translational momentum, a property desirable for spintronic and computing technologies. It has recently been proposed that such fermions may exist at the edges of certain types of topologically ordered insulators. Here, the realization and characterization of such a system is reported; the results reveal nearly 100 per cent spin polarization, even up to room temperature.

The magneto-optical Kerr effect is demonstrated in an antiferromagnetic metal. Large rotation angles, magnetic octupole domain imaging was enabled.

The impulsively driven antiferromagnetic Mott insulator is a model quantum many-body system predicted to realize exotic transient phenomena, however its exploration in far-from equilibrium regimes remains experimentally challenging. Here, the authors use a combination of second harmonic optical polarimetry and coherent magnon spectroscopy to investigate the ultrafast non-equilibrium dynamics of the Mott insulator Sr₂IrO₄ and find evidence of a far-from-equilibrium critical regime where static and dynamic critical behaviour decouple and which could be present in a number of other quantum materials.