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Recent work has expanded the concept of altermagnets to non-collinear magnetic materials. Here, Hu et al extend this further to non-collinear chiral materials, determining altermagnetic multipolar order parameters and predicting that such materials host large spin-hall and Edelstein effects.

The dynamics of hole-conjugated fractional quantum Hall states is poorly understood due to the limitations of current experimental probes. Here the authors study the high-frequency dynamics of edge modes at filling factor 2/3, precisely identifying the tunneling charge and damping of constituent charge modes.

Artificial magnetic fields enable topological transport in metamaterials. Here, authors realize a programmable optomechanical metamaterial where laser-induced synthetic magnetism gives rise to chiral phonon edge states characteristic of quantum-Hall-like behavior.

Quantum anomalous Hall crystals (QAHCs) combine the zero-field quantum Hall effect with spontaneously broken discrete translation symmetry. Here, the authors use exact diagonalization to demonstrate the existence of stable QAHCs arising from 2/3-filled moiré bands with Chern number C = 2.

The anomalous Hall effect is a macroscopic manifestation of a quantum mechanical effect. Here, Uelandet al. report the observation of a high Hall conductivity in the heavy-fermion compound UCu5, a metallic system, and explain its origin in terms of geometric frustration effects.

Graphene was one of the first materials proposed to host the quantum spin Hall effect. However, its weak intrinsic spin-orbit interaction means that observing such an effect requires modifying the graphene band structure. Here, Ghiasi et al. combine graphene with CrPS₄ and detect quantum spin Hall states at zero magnetic field.

The realization of the anomalous Hall effect in high-mobility two dimensional electron systems has so far remained elusive. Here, the authors observe its emergence in MgZnO/ZnO heterostructures and attribute it to skew scattering of electrons by localized paramagnetic centres.

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.

Previous models explain solid-solution strengthening by differences in atomic volume and electronegativity of the constituent atoms. Here, the authors consider both factors simultaneously and identify atomic volume as the dominant factor for FCC alloys.

Spin–orbit torques could enable a new generation of low-power electrically controlled memory devices. Here, the authors experimentally disentangle the spin-Hall effect and inverse spin-galvanic effect contributions to the relativistic spin torques in a room temperature Fe/(Ga,Mn)As bilayer.

Future information storage technology may exploit electrical currents to write the states of ferromagnetic nanoelements via spin torque effects. Here, the authors demonstrate such behaviour promoted by exchange bias from an interfaced antiferromagnet, which may help overcome practical device limitations.

The topological Hall effect usually results from a static scalar spin chirality. Here, through a combination of neutron scattering and transport measurements, Baral et al. demonstrate the emergence of a room temperature topological Hall effect due to dynamic scalar spin chirality in a topologically non-trivial phase in Fe3Ga4

It is predicted that fractionally charged skyrmions, topologically protected vortex-like spin configurations, may exist in systems exhibiting fractional quantum Hall states. Here, the authors demonstrate the existence of such objects in GaAs single quantum wells.

The electronic ground state of a correlated oxide interface is reversibly switched by light. Stemming from interfacial reconstructions, electrostatic confinement and photodoping, this effect opens a path towards engineering the optical response of oxides.

Anomalous Hall effect (AHE) in antiferromagnets is intriguing and requires further understanding. Here the authors report large AHE in a chiral-lattice antiferromagnet CoNb₃S₆ of which the origin can be due to complex magnetic texture or broken time-reversal symmetry on the electronic band structure.

A technique that allows the electrical detection of spin-polarized transport in semiconductors without disturbing the spin-polarized current or using magnetic elements has now been demonstrated. The approach could lead to the integration of spintronics elements into semiconductor microelectronic circuits.

Three-dimensional topological insulators are materials that are nonmagnetic insulators in the bulk but exhibit metallic surface states. Yoshimi et al, now identify a signature of such two-dimensional states, the quantum Hall effect, in bismuth-based chalcogenide topological insulators.

Andreev reflection is normally known to occur at a metal-superconductor interface. Here, Hashisaka et al. observe an Andreev-like process in a narrow junction between fractional and integer quantum Hall states originating from a topological quantum many-body effect instead of superconductivity.

Conduction in ferroelectric domain walls is now an established phenomenon, yet fundamental aspects of transport physics remain elusive. Here, Campbellet al. report the type, density and mobility of carriers in conducting domain walls in ytterbium manganite using nanoscale Hall effect measurements.

Electron-electron interactions in many-body systems may manifest themselves through the fractional quantum Hall effect. Here, the authors perform transport measurements in bilayer graphene, and observe particle-hole symmetric fractional quantum Hall states in theN=2 Landau level.

Metamaterials enable the control and manipulation of light on subwavelength scales, allowing numerous optical device applications. Here, the authors show the selective excitation of spatially confined modes in an anisotropic hyperbolic metamaterial, based on the photonic spin Hall effect.

There has been a recent surge in interest in using the orbital Hall effect to improve switching performance and expand the material options for spin-orbit torque driven magnetic memory. Here, Gupta et al demonstrate a significant improvement switching efficiency through integration of Ru in place of the more standard heavy metal, Pt.

Kwak et al. report AC magnetic parallel dipole line Hall measurements on electrochemical random-access memory based on WO_3-x, which determine the oxygen donor level and reveal that conductance potentiation even at low temperature is caused by an increase in both mobility and carrier density.

A superconductor placed near a quantum Hall edge can show emergent excitations with a range of exotic features. For instance, such heterostructures are predicted to exhibit non-local signatures that are direct extensions of ‘Andreev reflection’.

The anomalous Hall effect has been observed in high-quality epitaxial thin films of non-collinear antiferromagnet Mn₃Pt, and can be switched on and off using an electric field.

The fractional quantum Hall effect, occurring for rational Landau-level filling factors, is commonly observed in GaAs heterostructures. Now, unusual even-denominator fractional quantum Hall states are reported for an oxide 2D electron system.

Non-local transport measurements on mercury telluride quantum wells show clear signatures of the ballistic spin Hall effect. The ballistic nature of the experiment allows the observed effect to be interpreted as a direct consequence of the band structure of these semiconductor nanostructures, rather that being caused by impurity scattering.

Non-Hermitian systems can be described in terms of gain and loss with a coupled environment—a hard feature to tune in quantum devices. Now an experiment shows non-Hermitian topology in a quantum Hall ring without relying on gain and loss.

The authors report a Hall effect that originates from a fictitious magnetic field associated with antiferromagnetic order that breaks time-reversal symmetry, followed by translation symmetry.

Orbital angular momentum transfer from optical vortex beams to electronic quantum Hall states is reported in a graphene sheet, showing a robust contribution to the radial photocurrent that depends on the vorticity of light.

The effect of disorder in conventional two-dimensional electron systems is usually described in terms of individual electrons interacting with an underlying disorder potential. Scanning single-electron transistor measurements of graphene in a strong magnetic field indicate that in this system, coulombic interactions between electrons must also be taken into account.

Excitonic pairing in fractional quantum Hall states shows two new quantum phases, including a fractional exciton condensate and an unusual type of exciton that obeys fermionic or anyonic quantum statistics.

Graphene on boron nitride gives rise to a moiré superlattice displaying the Hofstadter butterfly: a fractal dependence of energy bands on external magnetic fields. Now, by means of capacitance spectroscopy, further aspects of this system are revealed—most notably, suppression of quantum Hall antiferromagnetism at particular commensurate magnetic fluxes.

Opto-twistronic Hall effect driven by structural chirality and coherence length is observed in a three-dimensional self-assembled twisted spiral superlattice of WS₂.

Skyrmion crystals, where skyrmions are arranged close packed in a triangular lattice arise due to the superposition of three magnetic spin spirals, each with a distinct wave vector, Q. Such skrymion crystals have been found in a diverse array of materials. Here, Park et al find a short wavelength (or dense skyrmion) limit of this skyrmion crystal structure in Co1/3TaS2, a metallic triangular lattice antiferromagnet, in the form of a triple Q magnetic ordering, with four magnetic sublattices.’

Magnetoresistance in ferromagnetic materials and heterostructures have been enabling advanced understanding of electron transport in solids, as well as new concepts for applications. Here the authors demonstrate a different type of magnetoresistance arising from anomalous Hall effect associated spin–charge mutual conversion.

Magnetic skyrmions are topologically protected magnetization textures which can arise in helical magnets and present promise for low-power nanoscale magnetic storage device applications. Here, the authors demonstrate extended phase stability and current-driven dynamics of skyrmions in nanowires of MnSi.

The authors demonstrate quantum Hall effect in semiconducting layered oxide Bi₂O₂Se. Its unique low mass among the oxides of 0.14 m_e and pronounced layered structure makes Bi₂O₂Se highly susceptible to the quantum confinement effects.

Non-Abelian anyons are exotic quasiparticles envisioned to be promising candidates for solid-state quantum computation. Clarkeet al. propose a device fabricated from fractional quantum Hall states and superconductors that supports a new type of non-Abelian defect that binds parafermionic zero modes.

We show that domain walls in minimally twisted bilayer graphene support exceptionally robust proximity superconductivity in the quantum Hall regime.

Non-zero topological charge prevents the straight motion of ferromagnetic skyrmions and hinders their applications. Here, the authors report the stabilization and current-driven dynamics of skyrmions in GdFeCo films in which the ferrimagnetic skyrmions can move with high velocity and reduced skyrmion Hall angle.

The relationship between the integer and fractional quantum Hall states are of fundamental importance in condensed matter physics. Here, the authors report a universality of phase transitions in both regimes in ultraclean trilayer graphene samples.

Electromagnetic responses can reveal the non-trivial properties of topological materials. Here, the authors demonstrate an anomalous planar Hall effect in trigonal crystals associated with the presence of topological nodal lines in trigonal-PtBi₂.