Owing to the coupling between open Fermi arcs on opposite surfaces, topological Dirac semimetals exhibit a new type of cyclotron orbit in the surface states known as Weyl orbit. Here, by lowering the carrier density in Cd₃As₂ nanoplates, we observe a crossover from multiple-frequency to single-frequency Shubnikov–de Haas (SdH) oscillations when subjected to out-of-plane magnetic field, indicating the dominant role of surface transport. With the increase of magnetic field, the SdH oscillations further develop into quantum Hall state with non-vanishing longitudinal resistance. By tracking the oscillation frequency and Hall plateau, we observe a Zeeman-related splitting and extract the Landau level index as well as sub-band number. Different from conventional two-dimensional systems, this unique quantum Hall effect may be related to the quantized version of Weyl orbits. Our results call for further investigations into the exotic quantum Hall states in the low-dimensional structure of topological semimetals.

Spin-lattice coupling plays an important role in both formation and understanding of the magnetism in two-dimensional magnetic semiconductors (2DMS). In this paper, the steady pressure effects on the lattice structure, Raman resonances, and magnetization of a 2DMS Cr₂Ge₂Te₆ have been studied by both experiments and first principles calculations. It is found that the bond length of Cr-Cr decreases, the angle of Cr-Te-Cr diverges from 90°, and the Raman modes ${\mathrm{E}}_{\mathrm{g}}^3$ and ${\mathrm{A}}_{\mathrm{g}}^1$ show an increase with the application of external pressure. Consequently, the magnetic phase transition temperature T_C decreases from 66.6 K to 60.6 K (∼9%) as the pressure increases from 0 to 1 GPa. These pressure effects not only confirm the existence of strong spin-lattice coupling but also reveal the detailed information about the lattice deformation effect on the magnetic properties in such 2DMS, which would be a benefit for the further understanding and manipulation of the magnetism in 2D materials.

1T-MoS₂ with a multilayered structure can be successfully synthesized by magneto-hydrothermal processing for flexible all-solid-state symmetric supercapacitor devices.

The coaction of the electric field induced strain and polarization effect on magnetic and electrical properties in field-effect structures, composing of ${\text{La}}_{0.7}{\text{Ca}}_{0.3}{\text{MnO}}_3$ (LCMO) films and $\text{Pb}\left({\text{Mg}}_{1/3}{\text{Nb}}_{2/3}\right){\text{O}}_3{\text{-PbTiO}}_3$ (PMN-PT) crystal, have been studied. The strain state of the films can continuously be tuned by application of bias electric field. The resistance variation in LCMO film is about $-4.34\%$ and $+3.48\%$ when a negative $\left(-8\text{kV}/\text{cm}\right)$ and positive $\left(+8\text{kV}/\text{cm}\right)$ bias field is applied, respectively, at 50 K. With increasing temperature, the field-dependent shuttlelike loop of relative resistance changes to butterflylike hysteresis loop under the coaction of field induced strain and polarization effect. Moreover, a sharp, stable, and reversal magnetization controlling effect caused by electric field has also been found in the structure. The magnetization decreases as much as $-8.64\%$ when a positive field 9.6 kV/cm is applied at 10 K. The data clearly show that the electric field induced strain effect is dominant for the magnetization, while the polarization is dominant for the effect on electrical transport properties when the LCMO is in ferromagnetic metal state. These results reveal that the electric field can tune the lattice distortion and carry distribution artificially as well as magnetic and electrical properties by using manganite/PMN-PT structure.