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<jats:p>As an elemental semiconductor, tellurium has recently attracted intense interest due to its non-trivial band topology, and the resulted intriguing topological transport phenomena. In this study we report systematic electronic transport studies on tellurium flakes grown via a simple vapor deposition process. The sample is self-hole-doped, and exhibits typical weak localization behavior at low temperatures. Substantial negative longitudinal magnetoresistance under parallel magnetic field is observed over a wide temperature region, which is considered to share the same origin with that in tellurium bulk crystals, <jats:italic>i.e.</jats:italic>, the Weyl points near the top of valence band. However, with lowering temperature the longitudinal magnetoconductivity experiences a transition from parabolic to linear field dependency, differing distinctly from the bulk counterparts. Further analysis reveals that such a modulation of Weyl behaviors in this low-dimensional tellurium structure can be attributed to the enhanced inter-valley scattering at low temperatures. Our results further extend Weyl physics into a low-dimensional semiconductor system, which may find its potential application in designing topological semiconductor devices.</jats:p>

<jats:p>The threshold voltage (<jats:italic>V</jats:italic> <jats:sub>th</jats:sub>) of the p-channel metal–oxide–semiconductor field-effect transistors (MOSFETs) is investigated via Silvaco-Atlas simulations. The main factors which influence the threshold voltage of p-channel GaN MOSFETs are barrier height <jats:italic>Φ</jats:italic> <jats:sub>1,p</jats:sub>, polarization charge density <jats:italic>σ</jats:italic> <jats:sub>b</jats:sub>, and equivalent unite capacitance <jats:italic>C</jats:italic> <jats:sub>oc</jats:sub>. It is found that the thinner thickness of p-GaN layer and oxide layer will acquire the more negative threshold voltage <jats:italic>V</jats:italic> <jats:sub>th</jats:sub>, and threshold voltage |<jats:italic>V</jats:italic> <jats:sub>th</jats:sub>| increases with the reduction in p-GaN doping concentration and the work-function of gate metal. Meanwhile, the increase in gate dielectric relative permittivity may cause the increase in threshold voltage |<jats:italic>V</jats:italic> <jats:sub>th</jats:sub>|. Additionally, the parameter influencing output current most is the p-GaN doping concentration, and the maximum current density is 9.5 mA/mm with p-type doping concentration of 9.5 × 10<jats:sup>16</jats:sup> cm<jats:sup>−3</jats:sup> at <jats:italic>V</jats:italic> <jats:sub>GS</jats:sub> = –12 V and <jats:italic>V</jats:italic> <jats:sub>DS</jats:sub> = –10 V.</jats:p>

<jats:p>Interlayer coupling in layered semiconductors can significantly affect their optoelectronic properties. However, understanding the mechanisms behind the interlayer coupling at the atomic level is not straightforward. Here, we study modulations of the electronic structure induced by the interlayer coupling in the <jats:italic>γ</jats:italic>-phase of indium selenide (<jats:italic>γ</jats:italic>-InSe) using scanning probe techniques. We observe a strong dependence of the energy gap on the sample thickness and a small effective mass along the stacking direction, which are attributed to strong interlayer coupling. In addition, the moiré patterns observed in <jats:italic>γ</jats:italic>-InSe display a small band-gap variation and nearly constant local differential conductivity along the patterns. This suggests that modulation of the electronic structure induced by the moiré potential is smeared out, indicating the presence of a significant interlayer coupling. Our theoretical calculations confirm that the interlayer coupling in <jats:italic>γ</jats:italic>-InSe is not only of the van der Waals origin, but also exhibits some degree of hybridization between the layers. Strong interlayer coupling might play an important role in the performance of <jats:italic>γ</jats:italic>-InSe-based devices.</jats:p>

<jats:p>Based on first-principles density functional theory calculation, we discover a novel form of spin-orbit (SO) splitting in two-dimensional (2D) heterostructures composed of a single Bi(111) bilayer stacking with a 2D semiconducting In<jats:sub>2</jats:sub>Se<jats:sub>2</jats:sub> or a 2D ferroelectric <jats:italic>α</jats:italic>-In<jats:sub>2</jats:sub>Se<jats:sub>3</jats:sub> layer. Such SO splitting has a Rashba-like but distinct spin texture in the valence band around the maximum, where the chirality of the spin texture reverses within the upper spin-split branch, in contrast to the conventional Rashba systems where the upper branch and lower branch have opposite chirality solely in the region below the band crossing point. The ferroelectric nature of <jats:italic>α</jats:italic>-In<jats:sub>2</jats:sub>Se<jats:sub>3</jats:sub> further enables the tuning of the spin texture upon the reversal of the electric polarization with the application of an external electric field. Detailed analysis based on a tight-binding model reveals that such SO splitting texture results from the interplay of complex orbital characters and substrate interaction. This finding enriches the diversity of SO splitting systems and is also expected to promise for spintronic applications.</jats:p>

<jats:p>The iron-chalcogenide superconductor FeTe<jats:sub>1–<jats:italic>x</jats:italic> </jats:sub>Se<jats:sub> <jats:italic>x</jats:italic> </jats:sub> displays a variety of exotic features distinct from iron pnictides. Although much effort has been devoted to understanding the interplay between magnetism and superconductivity near <jats:italic>x</jats:italic> = 0.5, the existence of a spin glass phase with short-range magnetic order in the doping range (<jats:italic>x</jats:italic> ∼ 0.1–0.3) has rarely been studied. Here, we use DC/AC magnetization and (quasi) elastic neutron scattering to confirm the spin-glass nature of the short-range magnetic order in a Fe<jats:sub>1.07</jats:sub>Te<jats:sub>0.8</jats:sub>Se<jats:sub>0.2</jats:sub> sample. The AC-frequency dependent spin-freezing temperature <jats:italic>T</jats:italic> <jats:sub>f</jats:sub> generates a frequency sensitivity Δ<jats:italic>T</jats:italic> <jats:sub>f</jats:sub>(<jats:italic>ω</jats:italic>)/[<jats:italic>T</jats:italic> <jats:sub>f</jats:sub>(<jats:italic>ω</jats:italic>)Δlog<jats:sub>10</jats:sub> <jats:italic>ω</jats:italic>] ≈ 0.028 and the description of the critical slowing down with <jats:italic>τ</jats:italic> = <jats:italic>τ</jats:italic> <jats:sub>0</jats:sub>(<jats:italic>T</jats:italic> <jats:sub>f</jats:sub>/<jats:italic>T</jats:italic> <jats:sub>SG</jats:sub> – 1)<jats:sup>−<jats:italic>z v</jats:italic> </jats:sup> gives <jats:italic>T</jats:italic> <jats:sub>SG</jats:sub> ≈ 22 K and <jats:italic>zv</jats:italic> ≈ 10, comparable to that of a classical spin-glass system. We have also extended the frequency-dependent <jats:italic>T</jats:italic> <jats:sub>f</jats:sub> to the smaller time scale using energy-resolution-dependent neutron diffraction measurements, in which the <jats:italic>T</jats:italic> <jats:sub>N</jats:sub> of the short-range magnetic order increases systematically with increasing energy resolution. By removing the excess iron through annealing in oxygen, the spin-freezing behavior disappears, and bulk superconductivity is realized. Thus, the excess Fe is the driving force for the formation of the spin-glass phase detrimental to bulk superconductivity.</jats:p>

<jats:p>Recently, the family of rare-earth chalcohalides were proposed as candidate compounds to realize the Kitaev spin liquid (KSL) [<jats:italic>Chin. Phys. Lett.</jats:italic> <jats:bold>38</jats:bold> 047502 (2021)]. In the present work, we firstly propose an effective spin Hamiltonian consistent with the symmetry group of the crystal structure. Then we apply classical Monte Carlo simulations to preliminarily study the model and establish a phase diagram. When approaching to the low temperature limit, several magnetic long range orders are observed, including the stripe, the zigzag, the antiferromagnetic (AFM), the ferromagnetic (FM), the incommensurate spiral (IS), the multi-<jats:italic> <jats:bold>Q</jats:bold> </jats:italic>, and the 120° ones. We further calculate the thermodynamic properties of the system, such as the temperature dependence of the magnetic susceptibility and the heat capacity. The ordering transition temperatures reflected in the two quantities agree with each other. For most interaction regions, the system is magnetically more susceptible in the <jats:italic>ab</jats:italic>-plane than in the <jats:italic>c</jats:italic>-direction. The stripe phase is special, where the susceptibility is fairly isotropic in the whole temperature region. These features provide useful information to understand the magnetic properties of related materials.</jats:p>

<jats:p>Due to the large exciton binding energy, two-dimensional (2D) transition metal dichalcogenides (TMDCs) provide an ideal platform for studying excitonic states and related photonics and optoelectronics. Polarization states lead to distinct light-matter interactions which are of great importance for device applications. In this work, we study polarized photoluminescence spectra from intralayer exciton and indirect exciton in WS<jats:sub>2</jats:sub> and WSe<jats:sub>2</jats:sub> atomic layers, and interlayer exciton in WS<jats:sub>2</jats:sub>/WSe<jats:sub>2</jats:sub> heterostructures by radially and azimuthally polarized cylindrical vector laser beams. We demonstrated the same in-plane and out-of-plane polarization behavior from the intralayer and indirect exciton. Moreover, with these two laser modes, we obtained interlayer exciton in WS<jats:sub>2</jats:sub>/WSe<jats:sub>2</jats:sub> heterostructures with stronger out-of-plane polarization, due to the formation of vertical electric dipole moment.</jats:p>

<jats:p>Grain boundary directed spinodal decomposition has a substantial effect on the microstructure evolution and properties of polycrystalline alloys. The morphological selection mechanism of spinodal decomposition at grain boundaries is a major challenge to reveal, and remains elusive so far. In this work, the effect of grain boundaries on spinodal decomposition is investigated by using the phase-field model. The simulation results indicate that the spinodal morphology at the grain boundary is anisotropic bicontinuous microstructures different from the isotropic continuous microstructures of spinodal decomposition in the bulk phase. Moreover, at grain boundaries with higher energy, the decomposed phases are alternating <jats:italic>α</jats:italic>/<jats:italic>β</jats:italic> layers that are parallel to the grain boundary. On the contrary, alternating <jats:italic>α</jats:italic>/<jats:italic>β</jats:italic> layers are perpendicular to the grain boundary.</jats:p>

<jats:p>Perovskite materials show exciting potential for light-emitting diodes (LEDs) owing to their intrinsically high photoluminescence efficiency and color purity. The research focusing on perovskite light-emitting diodes (PeLEDs) has experienced an exponential growth in the past six years. The maximum external quantum efficiency of red, green, and blue PeLEDs has surpassed 20%, 20%, and 10%, respectively. Nevertheless, the current PeLEDs are still in the laboratory stage, and the key for further development of PeLEDs is large-area fabrication. In this paper, we briefly discuss the similarities and differences between manufacturing high-quality and large-area PeLEDs and perovskite solar cells. Especially, the general technologies for fabricating large-area perovskite films are also introduced. The effect of charge transport layers and electrodes on large-area devices are discussed as well. Most importantly, we summarize the advances of large-area (active area ≥ 30 mm<jats:sup>2</jats:sup>) PeLEDs reported since 2017, and describe the methods for optimizing large-area PeLEDs reported in the literature. Finally, the development perspective of PeLEDs is presented for the goal of highly efficient and large-area PeLED fabrication. It is of great significance for the application of PeLEDs in future display and lighting.</jats:p>

<jats:p>Layered ReS<jats:sub>2</jats:sub> with direct bandgap and strong in-plane anisotropy shows great potential to develop high-performance angle-resolved photodetectors and optoelectronic devices. However, systematic characterizations of the angle-dependent photoresponse of ReS<jats:sub>2</jats:sub> are still very limited. Here, we studied the anisotropic photoresponse of layered ReS<jats:sub>2</jats:sub> phototransistors in depth. Angel-resolved Raman spectrum and field-effect mobility are tested to confirm the inconsistency between its electrical and optical anisotropies, which are along 120° and 90°, respectively. We further measured the angle-resolved photoresponse of a ReS<jats:sub>2</jats:sub> transistor with 6 diagonally paired electrodes. The maximum photoresponsivity exceeds 0.515 A⋅W<jats:sup>−1</jats:sup> along <jats:italic>b</jats:italic>-axis, which is around 3.8 times larger than that along the direction perpendicular to <jats:italic>b</jats:italic> axis, which is consistent with the optical anisotropic directions. The incident wavelength- and power-dependent photoresponse measurement along two anisotropic axes further demonstrates that <jats:italic>b</jats:italic> axis has stronger light–ReS<jats:sub>2</jats:sub> interaction, which explains the anisotropic photoresponse. We also observed angle-dependent photoresistive switching behavior of the ReS<jats:sub>2</jats:sub> transistor, which leads to the formation of angle-resolved phototransistor memory. It has simplified structure to create dynamic optoelectronic resistive random access memory controlled spatially through polarized light. This capability has great potential for real-time pattern recognition and photoconfiguration of artificial neural networks (ANN) in a wide spectral range of sensitivity provided by polarized light.</jats:p>