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A study conducted at Shandong University in Jinan, People's Republic of China, explores the engineering of the topological spin Hall effect in 2D multiferroic materials. The research focuses on the controllable and reversible manipulation of this phenomenon, which has implications for spintronics. By coupling antiferromagnetic topological charge with Dzyaloshinskii-Moriya interaction chirality, the study demonstrates a new approach to utilizing the topological spin Hall effect. This research opens up possibilities for further advancements in spintronics technology. [Extracted from the article]

• A 900 nm-thick tungsten film with novel double-layer architecture was prepared by high vacuum magnetron sputtering method. • β-W nucleation is intrinsically favoured on the SiO 2 substrate due to its low surface energy, based on thermodynamic calculation. • The preferred orientation of β-W changes from [200] to [211] with rising layer thickness, which is mainly controlled by elastic strain energy. • The β→α phase transformation is fulfilled by α/β interface propagation rather than local atomic rearrangements. Metastable phase in tungsten film is of great interests in recent years due to its giant spin Hall effects, however, little information has been known on its nucleation, growth and phase transformation. In this paper, a 900 nm-thick tungsten film with double-layer structure (α-W underlayer and β-W above it) was produced on SiO 2 /Si substrate by high vacuum magnetron sputtering at room temperature. The structural properties of β-W were systemically investigated by X-ray diffraction, transmission electron microscopy, thermodynamic calculation, first-principle and phase-field simulations. It is found that the β-W nucleation is energetically favoured on the SiO 2 surface compared to the α-W one. As the film thickening proceeds, β-W[211] turns to be preferred direction of growth owing to the elastic strain energy minimization, which is verified by phase-field simulations. Moreover, the β → α phase transformation takes place near the film-substrate interface while the rest of the film keeps the β-W phase, leading to a double-layer structure. This localized phase transition is induced by lower Gibbs free energy of α-W phase at larger grain sizes, which can be confirmed by thermodynamic calculation. Further in-situ heating TEM analysis of the as-deposited film reveals that the β→α phase transformation is fulfilled by α/β interface propagation rather than local atomic rearrangements. Our findings offer valuable insights into the intrinsic properties of metastable phase in tungsten. [Display omitted] [ABSTRACT FROM AUTHOR]

A new report discusses research on quantum materials conducted at Ion and Electron Beams (Dalian University of Technology). The study focuses on chiral materials and their coupling of spins and chirality through spin-orbit interaction, which has led to the emerging field of chiral spintronics. The researchers assembled chiral superatomic crystals using telluride tetrahedra clusters as building blocks, demonstrating unique spin textures and anisotropic spin Hall effect. These findings provide a new approach to accessing chirality-driven quantum effects through the assembly of superatomic crystals with designated symmetry and hierarchical structures. The research was funded by the National Natural Science Foundation of China. [Extracted from the article]

Keywords for this news article include: Bucharest, Romania, Europe, Cancer, Health and Medicine, Oncology, Politehnica University of Bucharest. Keywords: Bucharest; Romania; Europe; Cancer; Health and Medicine; Oncology EN Bucharest Romania Europe Cancer Health and Medicine Oncology 717 717 1 09/11/23 20230912 NES 230912 2023 SEP 12 (NewsRx) -- By a News Reporter-Staff News Editor at Cancer Weekly -- Current study results on Cancer have been published. (Springer - www.springer.com; Plasmonics - www.springerlink.com/content/1557-1955/) The news correspondents report that additional information may be obtained from Vasile A. Popescu, Politehnica University of Bucharest, Dept. of Physics, Splaiul Independentei 313, Bucharest 060042, Romania. [Extracted from the article]

Campinas, Brazil, South America, Chirality, Emerging Technologies, Health and Medicine, Nanoparticles, Nanotechnology Keywords: Campinas; Brazil; South America; Chirality; Emerging Technologies; Health and Medicine; Nanoparticles; Nanotechnology EN Campinas Brazil South America Chirality Emerging Technologies Health and Medicine Nanoparticles Nanotechnology 2023 FEB 12 (NewsRx) -- By a News Reporter-Staff News Editor at Medical Devices & Surgical Technology Week -- Investigators publish new report on Nanotechnology - Nanoparticles. [Extracted from the article]

Hierarchical temporal memory (HTM) tries to mimic the computing in cerebral neocortex. It identifies spatial and temporal patterns in the input for making inferences. This may require a large number of computationally expensive tasks, such as dot product evaluations. Nanodevices that can provide direct mapping for such primitives are of great interest. In this paper, we propose that the computing blocks for HTM can be mapped using low-voltage, magnetometallic spin-neurons combined with an emerging resistive crossbar network, which involves a comprehensive design at algorithm, architecture, circuit, and device levels. Simulation results show the possibility of more than $200\times$ lower energy as compared with a 45-nm CMOS ASIC design. [ABSTRACT FROM AUTHOR]

Spin Hall effects are a collection of relativistic spin-orbit coupling phenomena in which electrical currents can generate transverse spin currents and vice versa. Despite being observed only a decade ago, these effects are already ubiquitous within spintronics, as standard spin-current generators and detectors. Here the theoretical and experimental results that have established this subfield of spintronics are reviewed. The focus is on the results that have converged to give us the current understanding of the phenomena, which has evolved from a qualitative to a more quantitative measurement of spin currents and their associated spin accumulation. Within the experimental framework, optical-, transport-, and magnetization-dynamics-based measurements are reviewed and linked to both phenomenological and microscopic theories of the effect. Within the theoretical framework, the basic mechanisms in both the extrinsic and intrinsic regimes are reviewed, which are linked to the mechanisms present in their closely related phenomenon in ferromagnets, the anomalous Hall effect. Also reviewed is the connection to the phenomenological treatment based on spin-diffusion equations applicable to certain regimes, as well as the spin-pumping theory of spin generation used in many measurements of the spin Hall angle. A further connection to the spin-current-generating spin Hall effect to the inverse spin galvanic effect is given, in which an electrical current induces a nonequilibrium spin polarization. This effect often accompanies the spin Hall effect since they share common microscopic origins. Both can exhibit the same symmetries when present in structures comprising ferromagnetic and nonmagnetic layers through their induced current-driven spin torques or induced voltages. Although a short chronological overview of the evolution of the spin Hall effect field and the resolution of some early controversies is given, the main body of this review is structured from a pedagogical point of view, focusing on well-established and accepted physics. In such a young field, there remains much to be understood and explored, hence some of the future challenges and opportunities of this rapidly evolving area of spintronics are outlined. [ABSTRACT FROM AUTHOR]

Sums of matrix elements of spin-dependent two-body momentum-independent interactions and sums of their products are calculated analytically in the basis of many-body states with given total spin--the states built from spin and spatial wave functions belonging to multidimensional irreducible representations of the symmetric group, unless the total spin has the maximal allowed value. As in the first part of the series [V. A. Yurovsky, Phys. Rev. A 91, 053601 (2015)], the sum dependence on the many-body states is given by universal factors, which are independent of the Hamiltonians of noninteracting particles. The sum rules are applied to perturbative analysis of energy spectra and to calculation of two-body spin-dependent local correlations. [ABSTRACT FROM AUTHOR]

In the spin Hall effect of light (SHEL) with an incident linear polarization, the left circularly polarized (LCP) and the right circularly polarized (RCP) spin components are transversely shifted to opposite sides of the incident plane. We find that each spin component of the reflected or the refracted light is actually the coherent superposition of a pair with the same handedness. The two parts in a pair are generated by both the incident LCP and RCP components, respectively, and have different transverse shifts. Their weighted shifts lead to the overall displacement of the corresponding spin component. This perspective can successfully elucidate the dependence of the SHEL spin separations on the angle of polarization of the incident electric field. [ABSTRACT FROM AUTHOR]

Weak measurement is an important technique for the detection of the tiny spin-dependent splitting in photonic spin Hall effect. The weak measurement is only valid when the probe wave function remains almost undisturbed during the procedure of measurements. However, it does not always satisfy such condition in some practical situations, such as in the strong-coupling regime or when the preselected and postselected states are nearly orthogonal. In this paper, we develop a modified weak measurement for the detection of the photonic spin Hall effect when the probe wave function is distorted. We find that the measuring procedure with preselected and postselected ensembles is still effective. This scheme is important for us to detect the photonic spin Hall effect in the case where neither weak nor strong measurements can detect the spin-dependent splitting. The modified theory is valid not only in the weak-coupling regime but also in the strong-coupling regime, and especially in the intermediate regime. The theoretical models of conventional weak measurements and modified weak measurements are established and compared. We show that the experimental results coincide well with the predictions of the modified theory. [ABSTRACT FROM AUTHOR]

We generate spin currents in an 87Rb spin-2 Bose-Einstein condensate by application of a magnetic field gradient. The spin current destroys the spin polarization, leading to a sudden onset of two-body collisions. In addition, the spin coherence, as measured by the fringe contrast using Ramsey interferometry, is reduced drastically but experiences a weak revival due to in-trap oscillations. The spin current can be controlled using periodic π pulses (bang-bang control), producing longer spin-coherence times. Our results show that spin coherence can be maintained even in the presence of spin currents, with applications to quantum sensing in noisy environments. [ABSTRACT FROM AUTHOR]

When a gauge potential is constructed from the Berry phase, there is an associated scalar potential coming with the gauge potential. In this paper, we investigate the impact of this scalar potential on cold atoms by constructing an artificial gauge potential in a cold-atomic system. We interpret the scalar potential as the coupling between the atom and the mass of the non-Abelian part of the gauge potential. We demonstrate that the gauge potential can produce spin-orbit coupling and that the scalar potential will suppress the spin Hall currents which are generated by spin-orbit coupling. We also discuss the observation of these phenomena in a real experiment. [ABSTRACT FROM AUTHOR]

Several approaches to the semiclassical dynamics of fermions have been proposed in the past. The main subject under discussion was the inclusion of the Pauli principle, i.e., the fact that two electrons with parallel spins must be in orthogonal states. In the past, this was sometimes achieved by adding repulsive Pauli potentials or by using antisymmetric trial states. In this article we show that (a) the use of semiclassical propagators based on classical trajectories is sufficient to account for the Pauli principle, but (b) a semiclassical wave-function approach is not satisfactory. [ABSTRACT FROM AUTHOR]

The interactions between polarized Laguerre-Gaussian beams and clusters of metallic nanoparticles have been investigated by means of the nonlinear multiple scattering method. The near-field phase singularities and vorticity in the longitudinal component of the second-harmonic field have been discussed. We have found that the phase profile of the second-harmonic field is twice as many helicities as that of the fundamental frequency field. The spin-based second-harmonic generations--spatial splitting of spin states and spin-Hall effect of the second-harmonic field--have been observed. A class of spin-based second-harmonic generation devices is anticipated. [ABSTRACT FROM AUTHOR]

In this paper we theoretically investigate the photonic spin Hall effect (SHE) of a Gaussian beam reflected from the interface between air and topological insulators (TIs). The photonic SHE is attributed to spin-orbit coupling and manifests itself as in-plane and transverse spin-dependent splitting. We reveal that the spin-orbit coupling effect in TIs can be routed by adjusting the axion angle variations. We find that, unlike the transverse spin-dependent splitting, the in-plane one is sensitive to the axion angle. It is shown that the polarization structure in the magneto-optical Kerr effect is significantly altered due to the spin-dependent splitting in the photonic SHE. We theoretically propose a weak measurement method to determine the strength of axion coupling by probing the in-plane splitting of the photonic SHE. [ABSTRACT FROM AUTHOR]

We study the influence of topological defects on the spin current as well as the spin Hall effect. We find that the nontrivial deformation of the space time due to topological defects can generate a spin-dependent current which then induces an imbalanced accumulation of spin states on the edges of the sample. The corresponding spin Hall conductivity has also been calculated for the topological defect of a cosmic string. Compared to the ordinary value, a correction which is linear with mass density of the cosmic string appears. Our approach to the dynamics of nonrelativistic spinors in the presence of a topological defect is based on the Foldy-Wouthuysen transformation. The spin current is obtained by using the extended Drude model, which is independent of the scattering mechanism. [ABSTRACT FROM AUTHOR]

• Magnetic anomalous diffusion is observed in a rod-shaped specimen. • Fractional derivatives are used for the anomalous diffusion simulation. • Eddy current testing experimental device is simulated. • Accurate simulation results on significant frequency bandwidths are obtained. Electromagnetic evaluations are performed daily by steel manufacturers and steel user companies. Among different methods, Eddy Current Testing (ECT) is routinely used. It is versatile, simple, and conveys rich information. ECT evaluations on steel specimens remain complex to interpret quantitatively. Most steels are ferromagnetic and exhibit high nonlinear magnetic behaviors. Such nonlinearities are an issue when it comes to signal analysis and interpretation. The magnetic field diffusion in a steel rod is highly frequency-dependent. It is the direct consequence of the Eddy current generation. If the rod is ferromagnetic, the unstable distribution of the magnetic domains interacts with the macroscopic Eddy current circulation and perturbs the magnetic field diffusion, which becomes anomalous. Fractional derivative diffusion equations are appropriate tools for the simulation of these phenomena. The fractional order acts as an adjustment parameter that provides flexibility in the simulation method. In this study, a 2D fractional diffusion equation has been solved by using finite differences in polar coordinates to anticipate the magnetic field diffusion and the ECT measurement in a steel rod specimen. Defects have been simulated through local variations of the physical properties. Good simulation results have been obtained and validate the fractional diffusion equation as an efficient method for the simulation of the anomalous diffusion magnetic field and the interpretation of ECT measurements. [ABSTRACT FROM AUTHOR]

Spin Hall effect (SHE) is the generation of spin current due to an electric field, and has been observed in a variety of materials. In this work, we use linear response theory to verify that the analogous spin Hall current can be induced by chemical potential and temperature gradient, both of which are present in hot and dense nuclear matter created in heavy-ion collisions. We propose to measure "directed spin flow", the first Fourier coefficients of local spin polarization of Λ (Λ) hyperon, at central collisions to probe spin Hall current in heavy-ion collision experiments. We benchmark the magnitude of the induced "directed spin flow" at two representatively collisions energies, namely √sNN=200 GeV and √sNN=19.6 GeV, by employing a phenomenologically motivated freeze-out prescription. At both beam energies, the resulting "directed spin flow" ranges from 10-4 to 10-3, and is very sensitive to the rapidity. [ABSTRACT FROM AUTHOR]

The propagation of high-frequency gravitational waves can be analyzed using the geometrical optics approximation. In the case of large but finite frequencies, the geometrical optics approximation is no longer accurate and polarization-dependent corrections at first order in wavelength modify the propagation of gravitational waves, via a spin-orbit coupling mechanism. We present a covariant derivation from first principles of effective ray equations describing the propagation of polarized gravitational waves, up to first-order terms in wavelength, on arbitrary spacetime backgrounds. The effective ray equations describe a gravitational spin Hall effect for gravitational waves and are of the same form as those describing the gravitational spin Hall effect of light, derived from Maxwell's equations. [ABSTRACT FROM AUTHOR]

The propagation of electromagnetic waves in vacuum is often described within the geometrical optics approximation, which predicts that wave rays follow null geodesics. However, this model is valid only in the limit of infinitely high frequencies. At large but finite frequencies, diffraction can still be negligible, but the ray dynamics becomes affected by the evolution of the wave polarization. Hence, rays can deviate from null geodesics, which is known as the gravitational spin Hall effect of light. In the literature, this effect has been calculated ad hoc for a number of special cases, but no general description has been proposed. Here, we present a covariant Wentzel-Kramers-Brillouin analysis from first principles for the propagation of light in arbitrary curved spacetimes. We obtain polarization-dependent ray equations describing the gravitational spin Hall effect of light. We also present numerical examples of polarization-dependent ray dynamics in the Schwarzschild spacetime, and the magnitude of the effect is briefly discussed. The analysis reported here is analogous to that of the spin Hall effect of light in inhomogeneous media, which has been experimentally verified. [ABSTRACT FROM AUTHOR]

Gravitons possess a Berry curvature due to their helicity. We derive the semiclassical equations of motion for gravitons taking into account the Berry curvature. We show that this quantum correction leads to the splitting of the trajectories of right- and left-handed gravitational waves in curved space, and that this correction can be understood as a topological phenomenon. This is the spin Hall effect (SHE) of gravitational waves. We find that the SHE of gravitational waves is twice as large as that of light. Possible future observations of the SHE of gravitational waves can potentially test the quantum nature of gravitons beyond the classical general relativity. [ABSTRACT FROM AUTHOR]

The photonic spin Hall effect (SHE) can be regarded as a direct optical analogy of the SHE in electronic systems where a refractive index gradient plays the role of an electric potential. However, it has been demonstrated that the effective refractive index fails to adequately explain the light-matter interaction in atomically thin crystals. In this paper, we examine the spin-orbit interaction on the surface of the freestanding atomically thin crystals. We find that it is not necessary to involve the effective refractive index to describe the spin-orbit interaction and the photonic SHE in the atomically thin crystals. The strong spin-orbit interaction and giant photonic SHE are predicted, which can be explained as the large polarization rotation of plane-wave components in order to satisfy the transversality of photon polarization. [ABSTRACT FROM AUTHOR]

We show that in the presence of a three-dimensional (Weyl) spin-orbit coupling, a transverse spin current is generated in response to either a constant spin-independent force or a time-dependent Zeeman field in an arbitrary direction. This effect is the non-Abelian counterpart of the universal intrinsic spin Hall effect characteristic of the two-dimensional Rashba spin-orbit coupling. We quantify the strength of such an omnidirectional spin Hall effect by calculating the corresponding conductivity for fermions and noncondensed bosons. The absence of any kind of disorder in ultracold-atom systems makes the observation of this effect viable. [ABSTRACT FROM AUTHOR]

Planar microcavities allow the control and manipulation of spin polarization, manifested in phenomena like the optical spin Hall effect due to the intrinsic polarization mode splitting. Here, we study a transparent microcavity with broken rotational symmetry, realized by aligning the optic axis of a uniaxial cavity material in the cavity plane, giving rise to exceptional points in the dispersion relation. These occur pairwise, are circularly polarized, and are cores of polarization vortices. The exceptional points are result of the non-Hermitian character of the system and are in close relationship to singular optic axes in absorptive biaxial systems. [ABSTRACT FROM AUTHOR]

We examine the photonic spin Hall effect (SHE) in a graphene-substrate system with the presence of an external magnetic field. In the quantum Hall regime, we demonstrate that the in-plane and transverse spin-dependent splittings in the photonic SHE exhibit different quantized behaviors. The quantized SHE can be described as a consequence of a quantized geometric phase (Berry phase), which corresponds to the quantized spin-orbit interaction. Furthermore, an experimental scheme based on quantum weak value amplification is proposed to detect the quantized SHE in the terahertz frequency regime. By incorporating the quantum weak measurement techniques, the quantized photonic SHE holds great promise for detecting quantized Hall conductivity and the Berry phase. These results may bridge the gap between the electronic SHE and photonic SHE in graphene. [ABSTRACT FROM AUTHOR]

We theoretically show that the spin Hall effect arises in a Bose-Einstein condensate (BEC) of neutral atoms interacting via the magnetic dipole-dipole interactions (MDDIs). Since the MDDI couples the total spin angular momentum and the relative orbital angular momentum of two colliding atoms, it works as a spin-orbit coupling. Thus, when we prepare a BEC in a magnetic sublevel m=0, thermally and quantum-mechanically excited atoms in the m=1 and -1 states feel the Lorentz-like forces in the opposite directions. This is the origin for the emergence of the spin Hall effect. We define the mass-current and spin-current operators from the equations of continuity and calculate the spin Hall conductivity from the off-diagonal current-current correlation function within the Bogoliubov approximation. We find that the correction of the current operators due to the MDDI significantly contributes to the spin Hall conductivity. A possible experimental situation is also discussed. [ABSTRACT FROM AUTHOR]

We propose and realize a radial spin Hall effect (SHE) of light by using a dielectric metasurface. The metasurface with radially varying optical axes introduces a Pancharatnam-Berry (PB) geometrical phase to the incident light. The spatial gradient of PB phase accounts for a shift in the momentum space and thus leads the light to split radially into two concentric rays with opposite spin in the position space, which is called a radial SHE. Further experiments verify that the magnitude of the splitting increases with the rotation rate of the optical-axis orientation and the propagation distance, thereby allowing for macroscopic observation of the SHE. We also find that the phase of the incident light influences the profiles of the two split rays, while the polarization determines their intensities. The results provide methods to tune the SHE of light by engineering metasurfaces and modulating the incident light, and this radial SHE may be extrapolated to other physical systems. [ABSTRACT FROM AUTHOR]

We use a self-consistent Hartree-Fock approximation with realistic Coulomb interactions for π-band electrons to explore the possibility of broken symmetry states in weakly disordered ABC-stacked trilayer graphene. The competition between gapped and gapless broken symmetry states and normal states is studied by comparing total energies. We find that gapped states are favored and that, unlike the bilayer case, gapless nematic broken symmetry states are not metastable. Among the gapped states, the layer antiferromagnetic state is favored over anomalous and spin Hall states. [ABSTRACT FROM AUTHOR]

An asymmetric triangular potential well provides the simplest model for the confinement of mobile electrons at the interface between two insulating oxides, such as LaAlO3 and SrTiO3 (LAO/STO). These electrons have been recently shown to exhibit a large spin-orbit coupling of the Rashba type, i.e., linear in the in-plane momentum. In this paper we study the intrinsic spin Hall effect due to Rashba coupling in an asymmetric triangular potential well. This is the minimal model that captures the asymmetry of the spin-orbit coupling on opposite sides of the interface. Besides splitting each subband into two branches of opposite chirality, the spin-orbit interaction causes the transverse wave function (i.e., the wave function in the z direction, perpendicular to the plane of the quantum well) to depend on the in-plane wave vector k. At variance with the standard Rashba model, the triangular well supports a nonvanishing intrinsic spin Hall conductivity, which is proportional to the square of the spin-orbit coupling constant and, in the limit of low carrier density, depends only on the effective mass renormalization associated with the k dependence of the transverse wave functions. The origin of the effects lies in the nonvanishing matrix elements of the spin current between subbands corresponding to different states of quantized motion perpendicular to the plane of the well. [ABSTRACT FROM AUTHOR]