Modified Spin Textures

Three dimensional magnetic nanostructures exhibit many new properties and phenomena due to the extra degree of freedom compared to two dimensional nanostructures. In article number 2200213, Vivian Ng and Ba Myint create a magnetic lattice by overlapping hour-glass structures arrays on a 2D antidot matrix through a self-aligned nanosphere lithography technique. The field reversal behaviour and magnetic properties of the 3D magnetic lattice are characterized by magnetic force microscopy and the spin-curvature display unique magnetic behaviour as a consequence of the interplay of magnetic coupling.

A 3D magnetic lattice created by stacking hour-glass structure (HGS) over a 2D antidot matrix is reported. The study shows how the magnetic spin texture of the 3D lattice along the hard axis is modified by the HGS via multivortices induced reversal process. A new method of comparing simulation and experimental results using a MATLAB divergence computation software is reported.

Herein, by applying a uniaxial strain up to 5%, the evolution of the Raman and photoluminescence spectra of bilayer MoS₂ with four different twist angles is investigated. Further, the phototransistor based on the 30°-twisted structure is constructed. Its photoresponsivity (R) and specific photodetectivity (D*) are improved by ≈20 and ≈100 times than those values of the 0°-twisted one, respectively.

This study investigates the electron–phonon coupling and the phonon anharmonicity in Raman-active modes (E _g and A _1g) in the exfoliated PdTe₂ nanoflakes based on temperature-dependent Raman scattering. Both E _g mode with a Gaussian lineshape and A _1g mode with a Fano line shape show nonlinear frequency redshift, linewidth broadening with temperature, revealing the different electron–phonon coupling constants.

Auxetics are materials characterized by a negative Poisson's ratio. They increase their transverse dimensions under uniaxial tension and decrease them under compression. Depending on the pressure, the auxetic and partially auxetic behavior of strongly anisotropic hard cyclic tetramers is shown. The crystalline phase of tetramers becomes partially auxetic below the pressure $p^{*}\approx 4.8$ and offers completely auxetic behavior above that pressure.

The linear photoelectric effect (PGE) phenomenon of devices composed of noncentral inversion symmetric monolayer MoTe₂ is investigated. The PGE photocurrent can be greatly enhanced by biaxial tensile stress and external bias voltage, and the high photoresponse can be tuned to the telecommunication band range. This work demonstrates further applications of MoTe₂ monolayer devices in integrated photonics.

Self-trapped excitons (STEs) are studied in 2D metal halide perovskite (MHP) van der Waals (vdW) heterojunctions based on the improved Pollmann–Büttner model, in which these exciton states are classified into the normal and abnormal STEs according to the magnitude of the correction of exciton binding energy.

Under the alternating current magnetic field, the phase transition of the ferromagnetic (FM) to antiferromagnetic (AFM) is promoted and the heating branch shifts at a rate of −8 K T⁻¹, which causes the thermal hysteresis of FeRh reduction of about 2 K. These phenomena may be attributed to the Zeeman energy and the periodic vibration of domain walls. This work provides a method for reduction of the thermal hysteresis of phase transition materials.

The proposed Co-layered LaCoSi material discloses the electronic state coupling between structural strain and defect distribution, where the bonding interaction between reactants and catalysts can be affected by the electronic reconfiguration at reactive sites. The catalytic activity of Co site is obviously enhanced by tensile strain, and the antibonding interaction between Co and adsorbed hydrogen is also enforced.

Voltage applied in the lateral configuration to the MAPI perovskite film formed between platinum electrodes causes a complex sequence of processes observed such as photoluminescence quenching, appearance of unstable contrastive pattern, and increase in its intensity after voltage termination. This behavior is explained by the variation of the spatial electric field strength distribution and by the formation of temporal luminescence quenchers.

Herein, comparison of resistive switching characteristics of polymannose-based thin film with (1–7 wt%) and without fullerene (C60) is presented. Endurance of devices with C60 in polymannose is better than without C60. Memory window and ON/OFF ratio are, respectively, reduced and increased as the concentration of C60 increases as it serves as interlock between molecular chains of polymannose.

The mobile ion-mediated electric field screening processes defining the current regimes along polarization times up to tens of hours are described for millimeter-thick perovskites via drift-diffusion numeric simulations.

This work determines the first calculation of the cluster state of the perovskite REFe_1−xCr_xO₃ system based on magnetic calculations using molecular field theory, using GdFe_0.5Cr_0.5O₃ as an example, and the calculations show that the system has some Fe- and Cr-rich cluster behavior. The calculated results are verified by the Mossbauer spectra.

Under continuous transformation, conventional topologically nontrivial square lattice unit cell can be turned into another nontrivial one, enabling to construct multiple topological photonic systems with their trivial counterparts. With such systems, one can not only realize multichannel beam splitting for edge states, but also obtain both spatially and spectrally separated corner states.

A set of microscopies and spectroscopies complemented with theoretical calculations consistently show that the mechanical and electrostatic properties near the grain boundary (GB) of chemical vapor deposition (CVD)-grown MoS₂ are distinct from the interior ones. The underlying mechanism is proposed to be that the edge stitching behavior of MoS₂ with a misorientation angle leads to structural corrugation due to lattice deformation.

The self-consistent phonon theory is used in the calculation of lattice thermal conductivities in strained and unstrained SrTiO₃. The lattice thermal conductivity of SrTiO₃ decreases by less than 20% under in-plane compressive or tensile strain. Intrinsic phonon scattering alone is unable to cause a large decrease of thermal conductivity up to 60% observed in the experiment.

The reaction behavior of hydrogen may be the key to understand light- and elevated temperature-induced degradation in silicon solar cells. The authors describe one aspect of its behavior, the gallium–hydrogen pair formation and subsequent dissociation phenomena, under varying injection and temperatures. The results may serve as a tool for hydrogen quantification in Ga-doped Si-wafers.

Hexagonal Al₂O₃/TiO₂/TiN nanotube sensor is investigated using Al₂O₃ template, the Ni imprinting and two-step anodization technique, as well as atomic layer deposition and DC sputtering techniques, are used. This work offers insights into the sensitivity of the sensor, which is increased from 3.2% to 16.4%, also a great response and recovery times of 3 and 35 s.

GaN nanowires with n-type capping layers are investigated. Si atoms are more likely to substitute Ga atoms to form an n-type capping layer. n-Type capping layer reduces the work function of the GaN material. The addition of Si atoms increases the possibility of charge transfer. Si atoms provide shallow donor energy level in the n-type GaN capping layer.