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Microwave radiation has a dramatic effect on the magneto-resistance of two-dimensional electron systems, even reducing it below zero. It is thought that this is the result of the formation of distinct current domains. Direct experimental evidence for these domains is now presented for the first time.

Humanity’s Last Exam, a multi-modal benchmark at the frontier of human knowledge, is designed to be an expert-level closed-ended academic benchmark with broad subject coverage.

Dynamic control of components is required for large-scale quantum photonic networks. Here, Kapfingeret al. show dynamic control of the interaction between two coupled photonic crystal nanocavities forming a photonic molecule. Tuning is achieved by using an electrically generated radio frequency surface acoustic wave.

Assessment of surface contamination shows that trace oxygen is a key factor influencing the trajectory and quality of graphene grown by low-pressure chemical vapour deposition, with oxygen-free synthesis showing increased reproducibility and quality.

Focused-ion beam (FIB) lithography enables high-resolution nanopatterning of 2D materials, but usually introduces significant damage. Here, the authors report a FIB-based fabrication technique to obtain high quality graphene superlattices with 18-nm pitch, which exhibit electronic transport properties similar to those of natural moiré systems.

Alfvén waves are fundamental plasma modes that provide a mechanism for the transfer of energy between particles and fields. Here the authors confirm experimentally the conservative energy exchange between Alfvén wave fields and plasma particles via high-resolution MMS observations of Earth’s magnetosphere.

Electronic transport measurements in a magnetic field on the topological Dirac semimetal Cd₃As₂ identify the predicted Weyl orbits that weave Fermi arcs and bulk states together; the Weyl orbits enable transfer of chirality from one node to another, and open up the possibility of controlling topological properties electronically.

Understanding of ordered phases of interacting electrons in 2D systems is a fundamental many-body physics problem. Here, the authors report unconventional fractional quantum Hall phases in graphene Corbino devices originating from residual interactions of composite fermions in partially filled higher Landau levels. They also demonstrate the exceptional strength of the Coulomb interactions in suspended graphene by reaching the field-induced Wigner crystal state.

Graphene quantum dots promise applications for spin and valley qubits; however a demonstration of phase coherent oscillations has been lacking. Here the authors report coherent charge oscillations and measurements of coherence times in highly tuneable double quantum dots in bilayer graphene.

Metal-oxide superlattices were found to possess coexisting phases; a ferroelectric phase and a vortex phase with electric toroidal order. Electric fields interconverted from one phase to another, potentially enabling new functionality.

The magnetic exchange interaction at buried interfaces between magnetic and non-magnetic materials can be probed by investigating the interaction of spin-polarized electrons with magnon modes in the ferromagnetic layer.

The ferroelectric properties of BiFeO₃ have been the subject of extensive study. Using a range of experimental tools and numerical modelling, it is now shown that its ferroic properties can also be manipulated by strain effects, giving rise to a variety of magnonic phenomena.

The electrodynamics of topological insulators has been predicted to show a new magnetoelectric term, but this hasn’t been observed. Here, Dziomet al. observe a universal Faraday rotation angle equal to the fine structure constant, evidencing the so-called topological magnetoelectric effect.

High-resolution STM/STS visualizes the fractionalization of flat moiré bands into discrete Hofstadter subbands in moiré graphene near the predicted second magic angle, and experimentally establishes several fundamental properties of the fractal Hofstadter energy spectrum.

Understanding dynamics of fermionic bound states is important for their potential application in quantum devices. Here the authors study zero temperature dynamics and dissipation of fermions bound on a moving goal-post shaped wire in superfluid ³He-B.

Linear magnetoresistance is a phenomenon observed in many material systems and could be used in magnetic field sensors. This paper uncovers its microscopic origin showing how it arises from multiple scattering of electrons by low-mobility islands within an inhomogeneous high-mobility semiconductor.

Application of extreme magnetic fields to a low-disorder 2D electron gas causes its electrons to reorder through an unexpected transition from a 2D to quasi-3D Wigner crystal state.

Moiré superlattices offer a rich platform fort the study of correlated and topological phases. Here, by using low-temperature magneto-transport measurements, the authors demonstrate electric-field induced switching between Chern states in twisted double-layer graphene in the Hofstadter regime.

Chiral superconducting states are expected to support a variety of exotic and potentially useful phenomena. Theoretical analysis suggests that just such a state could emerge in a doped graphene monolayer.

S. X. M. Riberolles et al. study the kagome Chern insulator TbMn₆Sn₆ via inelastic neutron scattering. They observe signatures of chiral and flat-band magnons, which are highly localized in real space and strongly damped in the time domain.

The boundaries of fractional quantum Hall states can host multiple, interacting one-dimensional edge modes, which test our understanding of strongly interacting systems. Here the authors observe the edge-mode equilibration transition that was predicted for the ν=2/3 fractional quantum Hall state.

Precise control of vibrational states coupled to electronic degrees of freedom could enable control over charge or magnetic order in a material. Here, the authors use a double-pulse photoexcitation combined with an X-ray probe to control vibrational states near the critical point of spin density wave in Cr films.

Quantifying the coupling underlying synchronization in forced turbulent oscillator flows through phase-amplitude reduction analysis is typically computationally demanding. Here, the authors propose a data-driven approach coupling Stuart-Landau oscillator models with unknown forcing dynamics and apply it to the study of the wake behind a D-shaped body subject to periodic blowing.

Quantum criticality is often found in metallic compounds that are close to being magnetic. What about insulators in which the electric moments are fluctuating? These too can be described by the same framework—over a wider temperature range than in quantum critical metals.

The torque contributions exerted by spin-polarized currents on magnetic structures are not fully understood due to the difficulty in discerning their relative weight. Pollardet al. propose a novel method to directly determine the value of the competing spin transfer torques by in-situLorentz microscopy.

Antiferromagnets are interesting materials for fast spintronics applications, but control of the antiferromagnetic order has been limited to bulk materials so far. Now, uniaxial strain is shown to align the Néel vector in MnPSe₃ down to the monolayer limit.

Optical lattices, generated by interfering laser beams, provide a platform for observing condensed-matter phenomena in ultracold-atom systems. By extending the lattice idea to a multimode cavity, it should be possible to observe even more complex effects, such as frustration, crystallization, glass phases and supersolidity.

As well as superconductivity, cuprate perovskites can exhibit many different exotic spin and charge ordering states. Adding to this, Rosen et al.identify a stark difference in the electronic structure of the cuprate Bi2201 between its surface and its bulk.

Liquid crystal mixtures are used in commercial applications and their composition affects their properties. Here Rahimiet al. use atomistic simulations to show that defects influence the molecular arrangement of the mixture components leading to a deviation of the local order from that of the bulk.

Electrons trapped to a two-dimensional plane can exhibit many exotic properties. Here, the authors use a technique that measures entropy per electron to explore the evolution of such a system from the Fermi liquid regime to a previously unexplored regime of a strongly correlated charged plasma.

Ferroelectricity in hafnia-based systems seems to be correlated with oxygen vacancy dynamics, but the coupling of this and ferroelectric response is rarely studied. Here it is shown that Hf_0.5Zr_0.5O₂ can be antiferroionic, with antiferroelectric behaviour coupled to surface electrochemistry.

A material weakly linking two superconductors may itself exhibit superconductivity whilst its material properties strongly influence the nature of the supercurrent. Here, the authors identify a supercurrent with p-wave symmetry in such a Josephson junction made of topologically non-trivial material.

Quantum Hall phases in two-dimensional systems have chiral edges, along which electrons propagate in one direction without backscattering. Here, the authors use nuclear magnetic resonance to demonstrate how chiral modes establish dynamical nuclear polarization in a quantum Hall ferromagnet.

Real-space mapping of the quantum Hall state at the Dirac point in epitaxial graphene reveals unexpected localized lifting of the degeneracy of this level. This could be the result of moiré interference caused by the twisting of the top layer with respect to underlying layers, suggesting possible new ways to understand and control the unusual properties of graphene.

Interfaces between topologically distinct phases reveal rich phenomenology. Here, Crépel et al. present a microscopic study on the low energy physics, interface gapless mode, identification of spin and charge excitations, etc. of the Halperin–Laughlin interface using recently proposed model wavefunctions.

The understanding of the magnetisation evolution upon femtosecond optical pumping remains elusive. The authors perform resonant X-ray magnetic scattering measurements and multiscale simulations that reveal rapid magnetic order recovery in ferrimagnets via nonlinear magnon processes.

Readout of remote spins in quantum dot arrays is a challenge for future quantum computing architectures. Here, the authors implement electron cascade for spin readout on quantum dots far away from a charge sensor in a quadruple quantum dot device and discuss its applicability to large-scale arrays.

The characteristic length scale and mechanism of the metal–insulator transition in nickelate superlattices is addressed, with implications for the design of oxide electronics.

Fractional quantum Hall states in 2D electron gases arise due to strong electron-electron interactions, which makes a general theoretical understanding difficult. Fu et al. present data showing the ν = 5/3 quantum Hall state has a 3/2 plateau in the diagonal resistance that has not been captured by existing models.

The nature of the fractional quantum Hall state when the lowest Landau level is half-filled remains controversial. Now, the observation of a topological phase transition at related filling fractions suggests that the half-filled state is non-Abelian.

The charge states in distant quantum dots can be coupled through an intermediate state in a third quantum dot.

Stimulated Raman scattering limits the energy of dissipative solitons by converting excess energy into noisy Raman pulses. Using delay compensation, Babin et al. demonstrate that these noisy pulses can become coherent Raman dissipative solitons leading to the formation of multicolour bound dissipative soliton complexes.