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Two dimensional materials are promising for electronic applications, which await the exploration of cooperative phenomena. Here, Liu et al. report switchable ferroelectric polarization in thin CuInP₂S₆film at room temperature, demonstrating good memory behaviour with on/off ratio of ∼100 based on two-dimensional ferroelectricity.

The study finds coherent spin waves, generated by ultrafast laser pulses, drive antiferromagnetic domain walls (DWs) in Sr₂Cu₃O₄Cl₂ at a record  ~50 km/s. DW propagation direction is controllable via laser helicity and DW winding number, explained by in-plane magnon mode-induced dynamics unique to easy-plane anisotropy magnets.

Van der Waals heterostructures offer a platform for harnessing the spin-valley degree of freedom for information processing. Here, the authors transfer optically generated spin-valley polarization from one layer to another in a two-dimensional molybdenum diselenide–tungsten diselenide heterostructure.

Controlling the individual layer magnetization in CrI₃ enables the observation of a layer-resolved magnetic proximity effect in WSe₂/CrI₃ heterostructures.

Searches for metastable states with properties not found in thermal equilibrium have been restricted to either ultrafast or slow timescales. A metastable state in an intermediate time window has now been identified in a photo-doped Mott insulator.

Atomically thin chromium tri-iodide is shown to be a 2D ferromagnetic insulator with an optical response dominated by ligand-field transitions, emitting circularly polarized photoluminescence with a helicity determined by the magnetization direction.

Polarization-resolved photoluminescence measurements reveal the anisotropic character of excitons in monolayer black phosphorus, which are found to have a large binding energy.

Second-order optical nonlinearities can be controlled, up to room temperature, by electrostatic gating in a field-effect transistor made from atomically thin crystals of WSe₂.

Electrical control of magnetism in a bilayer of CrI₃ enables the realization of an electrically driven magnetic phase transition and the observation of the magneto-optical Kerr effect in 2D magnets.

Electron–phonon coupling in a monolayer WSe₂ on a substrate is investigated by femtosecond surface X-ray scattering. Counterintuitively, the absorbed optical photon energy is dominantly coupled to the in-plane lattice vibrations within 1 ps.

The trapping of interlayer valley excitons in a moiré potential formed by a molybdenum diselenide/tungsten diselenide heterobilayer with twist angle control is reported.

Monolayer transition-metal dichalcogenide (TMD) is promising to host features of topological superconductivity. Here, de la Barrera et al. study layered compounds, 2H-TaS₂ and 2H-NbSe₂, in their atomic layer limit and find a largest upper critical field for an intrinsic TMD superconductor.

Moiré trions are observed in electrostatically gated WSe₂/MoSe₂ heterobilayers, where photoluminescence polarization switching reveals a competition between valley-flip and spin-flip relaxation pathways of photo-excited carriers during trion formation.

Magneto-optical Kerr effect microscopy is used to show that monolayer chromium triiodide is an Ising ferromagnet with out-of-plane spin orientation.

This Review discusses the contemporary experimental and theoretical understanding of interlayer excitons in heterobilayers of transition metal dichalcogenides.

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.

The energy extrema of an electronic band are referred to as valleys. In 2D materials, two distinguishable valleys can be used to encode information and explore other valleytronic applications.