Two-dimensional (2D) magnetic materials have attracted much recent interest with unique properties emerging at the few-layer limit. Beyond the reported impacts on the static magnetic properties, the effects of reducing the dimensionality on the magnetization dynamics are also of fundamental interest and importance for 2D device development. In this report, we investigate the spin dynamics in atomically thin antiferromagnetic FePS3 of varying layer numbers using ultrafast pump-probe spectroscopy.

Moiré superlattices of two-dimensional van der Waals materials have emerged as a powerful platform for designing electronic band structures and discovering emergent physical phenomena. A key concept involves the creation of long-wavelength periodic potential and moiré bands in a crystal through interlayer electronic hybridization or atomic corrugation when two materials are overlaid. Here we demonstrate a new approach based on spatially periodic dielectric screening to create moiré bands in a monolayer semiconductor.

Single spin arrays can serve as a scalable qubit platform. Here, we report the observation of arrays of single spins which are optically accessible through strain-induced localized positive trions residing in WSe2/CrI3 heterostructures. © 2021 OSA.

The strong excitonic effect in monolayer transition metal dichalcogenide (TMD) semiconductors has enabled many fascinating light-matter interaction phenomena. Examples include strongly coupled exciton-polaritons and nearly perfect atomic monolayer mirrors. The strong light-matter interaction also opens the door for dynamical control of mechanical motion through the exciton resonance of monolayer TMDs. Here, we report the observation of exciton-optomechanical coupling in a suspended monolayer MoSe2 mechanical resonator.

Moiré superlattices offer an unprecedented opportunity for tailoring interactions between quantum particles1–11 and their coupling to electromagnetic fields12–18. Strong superlattice potentials generate moiré minibands of excitons16–18—bound pairs of electrons and holes that reside either in a single layer (intralayer excitons) or in two separate layers (interlayer excitons). Twist-angle-controlled interlayer electronic hybridization can also mix these two types of exciton to combine their strengths13,19,20.

Magnetostriction, coupling between the mechanical and magnetic degrees of freedom, finds a variety of applications in magnetic actuation, transduction and sensing1,2. The discovery of two-dimensional layered magnetic materials3–8 presents a new platform to explore the magnetostriction effects in ultrathin solids. Here we demonstrate an exchange-driven magnetostriction effect in mechanical resonators made of two-dimensional antiferromagnetic CrI3. The mechanical resonance frequency is found to depend on the magnetic state of the material.

Strong magnetization fluctuations are expected near the thermodynamic critical point of a continuous magnetic phase transition. Such critical fluctuations are highly correlated and in principle can occur at any time and length scales1; they govern critical phenomena and potentially can drive new phases2,3. Although critical phenomena in magnetic materials have been studied using neutron scattering, magnetic a.c. susceptibility and other techniques4–6, direct real-time imaging of critical magnetization fluctuations remains elusive.

Quantum particles on a lattice with competing long-range interactions are ubiquitous in physics; transition metal oxides1,2, layered molecular crystals3 and trapped-ion arrays4 are a few examples. In the strongly interacting regime, these systems often show a rich variety of quantum many-body ground states that challenge theory2. The emergence of transition metal dichalcogenide moiré superlattices provides a highly controllable platform in which to study long-range electronic correlations5–12.

Isolated spins are the focus of intense scientific exploration due to their potential role as qubits for quantum information science. Optical access to single spins, demonstrated in III-V semiconducting quantum dots, has fueled research aimed at realizing quantum networks. More recently, quantum emitters in atomically thin materials such as tungsten diselenide have been demonstrated to host optically addressable single spins by means of electrostatic doping the localized excitons.