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Resistance switching in multilayer structures are typically based on materials possessing ferroic orders. Here we predict an extremely large resistance switching based on the relative spin-orbit splitting in twisted transition metal dichalcogenide (TMD) monolayers tunnel junctions. Because of the valence band spin splitting which depends on the valley index in the Brillouin zone, the perpendicular electronic transport through the junction depends on the relative reciprocal space overlap of the spin-dependent Fermi surfaces of both layers, which can be tuned by twisting one layer. Our quantum transport calculations reveal a switching resistance larger than 10 6 % when the relative alignment of TMDs goes from 0∘ to 60∘ and when the angle is kept fixed at 60∘ and the Fermi level is varied. By creating vacancies, we evaluate how inter-valley scattering affects the efficiency and find that the resistance switching remains large ( 10 4 % ) for typical values of vacancy concentration. Not only should this resistance switching be observed at room temperature due to the large spin splitting, but our results also show how twist angle engineering and control of van der Waals heterostructures could be used for next-generation memory and electronic applications.

Spin‐orbit coupling refers to the relativistic interaction between the spin and orbital motions of electrons. This interaction leads to numerous intriguing phenomena, including spin‐orbit torques, spin–momentum locking, topological spin textures, etc., that have recently gained prominence in the field of spin‐orbitronics. In particular, the emerging ferroelectric control is recognized and validated as an effective means to enhance energy efficiency across a broad spectrum of spin‐orbitronic devices. Here, cutting‐edge research on ferroelectric control of spin‐orbitronics (FECSO) by means of spontaneous polarization, reversible ferroelectric switching, and multiferroic coupling, are comprehensively reviewed. Two fascinating topics are mainly discussed: topological spin texture and spin‐charge interconversion. The classification of control mechanisms for different interactions in FECSO is summarized first. Then, from the perspective of material classification, the ferroelectric‐controlled spin‐orbit coupling with tunable topological spin texture in oxide systems, magnetic metal multilayers, and 2D van der Waals materials is reviewed. Subsequently, the ferroelectric‐tunable spin‐charge interconversion on heavy metal layers, oxide interfaces, and ferroelectric Rashba semiconductors is highlighted. In the end, the challenges and forthcoming prospects of FECSO are discussed. This work may provide pertinent and forward‐thinking guidance to accelerate the ongoing advancement of this field. [ABSTRACT FROM AUTHOR]

Spin–orbit coupling is widespread in binary asteroid systems, and it has been widely studied for the case of ellipsoidal secondary. Due to angular momentum exchange, dynamical coupling is stronger when the orbital and rotational angular momenta are closer in magnitudes. Thus, the spin–orbit coupling effects are significantly different for ellipsoidal secondaries and primaries. In the present work, a high-order Hamiltonian model in terms of eccentricity is formulated to study the effects of spin–orbit coupling for the case of ellipsoidal primary body in a binary asteroid system. Our results show that the spin–orbit coupling problem for the ellipsoidal primary holds two kinds of spin equilibrium, while there is only one for the ellipsoidal secondary. In particular, 1:1 and 2:3 spin–orbit resonances are further studied by taking both the classical pendulum approximation and adiabatic approximation (Wisdom's perturbative treatment). It shows that there is a critical value of total angular momentum, around which the pendulum approximation fails to work. Dynamical structures are totally different when the total angular momentum is on two sides of the critical value. [ABSTRACT FROM AUTHOR]

We report on the development of a "two-field-scan" harmonic Hall voltage (HHV) analysis, which collects the second HHV as a function of a swept in-plane magnetic field at 45° and 0° relative to the excitation current, for the determination of the spin-orbit torques of transverse spins in magnetic heterostructures without significant perpendicular spins, longitudinal spins, and longitudinal/perpendicular Oersted fields. We demonstrate that this two-field-scan analysis is as accurate as the well-established but time-consuming angle-scan HHV analysis even in the presence of considerable thermoelectric effects but takes more than a factor of 7 less measurement time. We also show that the fit of the HHV data from a single field scan at 0°, which is commonly employed in the literature, is not reliable because the employment of too many free parameters in the fitting of the very slowly varying HHV signal allows erroneous conclusion about the spin-orbit torque efficiencies. [ABSTRACT FROM AUTHOR]

Searching for controllable topological state by means of external stimuli in 2D material‐based van der Waals (vdW) heterostructures is currently an active field for both the underlying physics and practical applications. Herein, a vdW heterostructure formed by vertically stacking AlSb and InSe monolayers is designed and its stacking configuration, stability, electronic structure, and effect of external electric field are investigated using first‐principles calculations. The AlSb/InSe heterobilayer studied, possessing both dynamical and thermal stabilities, is direct bandgap semiconductor and forms a Z‐scheme heterojunction. With inclusion of spin–orbit coupling (SOC) and applying external electric field, the bandgap of AlSb/InSe heterobilayer decreases at first and then increases, and a trivial insulator to topological insulator phase transition is achieved. For the topological insulator phase, band inversion is ascribed to the strong SOC of p orbitals of Sb. In this work, the way is paved for the design and application of multifunctional nanoscale devices such as topological field‐effect transistor. [ABSTRACT FROM AUTHOR]

It is crucial to study the materials that could effectively facilitate the inter‐conversion between charge, spin, and orbital degrees of freedom. In this work, the conversion among these three types of degrees of freedom in Pt/CoFeB/rare‐earth (RE, represents Nd, Gd, and Ho)/Ti multilayers is manipulated. Through terahertz (THz) emission measurements, it is found that the spin current induced by a femtosecond laser is converted into an orbital current via the spin‐orbit coupling of the RE layer. Notably, the light RE (Nd) and heavy RE (Gd and Ho) induce the orbital current with opposite polarization directions, ultimately leading to a weakening or enhancement of the THz emission intensity, respectively. Moreover, the fast Fourier transform reveals that Gd exerts the most significant influence on increasing the whole THz spectrum within the Pt/CoFeB/RE/Ti structure. The findings of RE‐modulated spin‐to‐orbital conversion provide valuable insights into the fundamental transport mechanism of the orbital current. [ABSTRACT FROM AUTHOR]

In this work, we have systematacially investigated the electronic structure and spectroscopic properties of the HX+ (X = F, Cl, Br, I) cations by using the highly correlated MRCI + Q approach. This is the first comprehensive ab initio study on the electronic states of the HX+ cations. The spin–orbit coupling (SOC) effect is introduced with the state interaction approach. There are total 10 Λ-S and 18 Ω states obtained in the calculation. The results show that the potential energy curves' (PECs) shapes and structure of the electronic states of different HX+ cations exhibit the significant distinction due to the X-dependent energy-level order of the unique dissociation channel H+(1Sg) + X(2Pu). From PECs, the spectroscopic constants of the bound electronic states are determined, which are in good agreement with available observed values. Regarding HBr+ and HI+, the good agreement has been achieved only when the SOC effect is considered. The predissociation for the first excited A2Σ+ state of HCl+, HBr+, and HI+ is analyzed based on computed spin–orbit matrix elements. Around the equilibrium position, the energy splittings of X2Π are calculated to be 288, 661, 2691, and 5137 cm−1 for HF+, HCl+, HBr+, and HI+, respectively. It has been demonstrated that SOC is substantial for HX+, leading to significant changes in PECs' shapes as well as in electronic structure. Finally, the transition properties are predicted, including transition dipole moments, Franck–Condon factors, and radiative lifetimes. Both the Ω transitions A2Σ+ 1/2-X2Π3/2 and A2Σ+ 1/2-X2Π1/2 of the HX+ cations are determined to possess the radiative lifetimes at the microsecond (µs) level. [ABSTRACT FROM AUTHOR]

There are only limited theoretical results published on the transition properties of the X1Σ+, A1Π, B1Σ+, C1Δ, D1Σ−, E1Δ, a3Π, b3Σ+, and c3Δ states of BeS, and even some of the states have no theoretical and experimental reports on the relevant aspects of these transitions. Therefore, we derived these transition properties in this study. The potential energy curves of X1Σ+, A1Π, B1Σ+, C1Δ, D1Σ−, E1Δ, a3Π, b3Σ+, c3Δ, d3Σ−, and e3Σ− states of the BeS molecule with their Ω states and the transition dipole moments between them were calculated by the complete active space self-consistent field method, followed by the internally contracted multireference configuration interaction method. For the accurate computation of the transition properties, scalar relativistic corrections and core–valence correlation were considered. The radiative lifetimes were approximately 10−6 s for the A1Π and b3Σ+ states, 10−7 s for the E1Δ state, 10−7–10−8 s for the C1Δ and D1Σ− states, and 10−8 s for the B1Σ+, c3Δ, and e3Σ− states. The transition properties of the seven Ω states generated by the X1Σ+, A1Π, B1Σ+, and a3Π electronic states, including several electric dipole-forbidden transitions were researched. In particular, the B1Σ+0+–X1Σ+0+, B1Σ+0+–A1Π1, and A1Π1–X1Σ+0+ systems have strong transitions. In this paper, the radiative lifetimes of A1Π1, B1Σ+0+, a3Π0−, a3Π0+, and a3Π1 electronic states were also computed. For the A1Π1, B1Σ+0+, and a3Π1 states, the distribution of the radiation lifetime with the rotational angular momentum quantum number J at 0 ≤ υ ≤ 15 and J ≤ 70 was evaluated. It is expected that the outcome of the calculations in this paper can contribute some meaningful guidelines for conducting further theoretical and experimental investigations. [ABSTRACT FROM AUTHOR]

We investigate emergent conductive phenomena triggered by collinear antiferromagnetic orderings. We show that an up-down-zero spin configuration in a triangle cluster leads to linear and nonlinear spin conductivities even without the relativistic spin–orbit coupling; the linear spin conductivity is Drude-type, while the nonlinear spin conductivity has Hall-type characterization. We demonstrate the emergence of both spin conductivities in a breathing kagome system consisting of a triangle cluster. The nonlinear spin conductivity becomes larger than the linear one when the Fermi level lies near the region where a small partial band gap opens. Our results indicate that collinear antiferromagnets with triangular geometry give rise to rich spin conductive phenomena. [ABSTRACT FROM AUTHOR]

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We show in this paper that the technologically relevant field-like spin–orbit torque (SOT) shows resilience against the geometrical effect of electron backscattering. As a device grows smaller in size, the effect of geometry on physical properties like spin torque, and hence switching current could place a physical limit on the continued shrinkage of such a device — a necessary trend of all memory devices (MRAM). The geometrical effect of curves has been shown to impact quantum transport and topological transition of Dirac and topological systems. In our work, we have ruled out the potential threat of line curves degrading the effectiveness of SOT switching. In other words, SOT switching will be resilient against the influence of curves that line the circumferences of defects in the events of electron backscattering, which commonly happens in the channel of modern electronic devices. [ABSTRACT FROM AUTHOR]

The inner barrier in stepped quantum wells, which embrace an intrinsic structural inversion asymmetry (SIA), offers more possibilities for the multi-band spin–orbit (SO) control. By varying the inner band offset δ , which adjusts the quantum confinement for electrons and also the SIA, we reveal that both the Rashba ( α ν ) and Dresselhaus ( β ν ) SO coeffcients of the two subbands exhibit contrasting dependence on δ. Also, α 1 and α 2 may have opposite signs, depending on the value of δ. By fine tuning the inner offset, there may even exist a scenario in which α 2 identically vanishes but α 1 is finite, offering a knob on how to subband-selectively suppress spin relaxation induced by SO coupling. In addition, by resorting to an external gate V g , we reveal that in the regime of α 1 and α 2 having opposite signs, their magnitudes also vary with V g in an opposite manner. This, together with the engineered inner barrier of stepped wells, will facilitate flexible spin manipulation. Finally, the interband SO couplings, which depend on the spatial overlap of wave functions of distinct subbands and the corresponding parities, are also discussed. [ABSTRACT FROM AUTHOR]

Solar‐to‐chemical energy conversion thorugh photocatalytic technology has garnered significant attention due to its potential for clean hydrogen pro duction, pollutant degradation, and carbon dioxide reduction. However, its relatively low solar‐to‐chemical conversion efficiency hinders its industrial development. External fields have currently emerged as a supplementary energy source to augment the overall catalytic efficiency. Recently, the photocatalytic performance has been considerably enhanced through magnetic field modulation, which promotes the separation and transfer of photoexcited charge carriers. This article systematically reviews the recent research progress of magnetic field–assisted photocatalysis, discussing phenomena such as the negative magnetoresistance effect, Lorentz force, and spin polarization. It comprehensively analyzes the effect of magnetic fields on critical processes in photocatalysis: light absorption, charge‐carrier separation, and surface reactions. In particular, this review focuses on the spin‐relaxation mechanism, explains how the electron lifetime is extended through spin polarization, and proposes design strategies for spin‐polarized materials. Finally, this review discusses the challenges and potential opportunities for enhancing photocatalytic efficiency. The ultimate objective of this review is to offer notable theoretical and experimental insights that can guide the design and development of high‐performance photocatalysts and photocatalytic systems. [ABSTRACT FROM AUTHOR]

We consider two cases of spontaneous anomalous Hall current. In a non-magnetic system with spin–orbit coupling (SOC), the applied bias results in the appearance of non-equilibrium magnetization and an anomalous Hall current. The latter demonstrates non-linear dependence on the applied bias. In a magnetic system with SOC, an anomalous current appears without applied bias. We perform the calculations in the framework of the free-electron model, whereas the common approach to this type of phenomenon is based on Berry connection. We demonstrate that anomalous currents acquire a measurable magnitude for reasonable model parameters. [ABSTRACT FROM AUTHOR]

Converting CO2 into useful chemicals using metal catalysts is a significant challenge in chemistry. Among the various catalysts reported, transition metal lanthanide hybrid {3d–4f} complexes stand out for their superior efficiency and site selectivity. However, unlike transition metal catalysts, understanding the origin of this efficiency in lanthanides poses a challenge due to their orbital degeneracy, rendering the application of DFT methods ineffective. In this study, we employed a combination of density functional theory (DFT) and ab initio CASSCF/RASSI‐SO calculations to explore the mechanism of CO2 conversion to cyclic carbonate using a 3d–4f heterometallic catalyst for the first time. This work unveils the importance of 3d and 4f metal cooperativity and the role of individual spin‐orbit states in dictating the overall efficiency of the catalyst. [ABSTRACT FROM AUTHOR]

Purely organic molecules with room‐temperature phosphorescence (RTP) are potential luminescent materials with high exciton utilization for organic light‐emitting diodes (OLEDs), but those exhibiting superb electroluminescence (EL) performances are rarely explored, mainly due to their long phosphorescence lifetimes. Herein, a robust purely organic RTP molecule, 3,6‐bis(5‐phenylindolo[3,2‐a]carbazol‐12(5H)‐yl)‐xanthen‐9‐one (3,2‐PIC‐XT), is developed. The neat film of 3,2‐PIC‐XT shows strong green RTP with a very short lifetime (2.9 μs) and a high photoluminescence quantum yield (72 %), and behaviors balanced bipolar charge transport. The RTP nature of 3,2‐PIC‐XT is validated by steady‐state and transient absorption and emission spectroscopies, and the working mechanism is deciphered by theoretical simulation. Non‐doped multilayer OLEDs using thin neat films of 3,2‐PIC‐XT furnish an outstanding external quantum efficiency (EQE) of 24.91 % with an extremely low roll‐off (1.6 %) at 1000 cd m−2. High‐performance non‐doped top‐emitting and tandem OLEDs are also achieved, providing remarkable EQEs of 24.53 % and 42.50 %, respectively. Delightfully, non‐doped simplified OLEDs employing thick neat films of 3,2‐PIC‐XT are also realized, furnishing an excellent EQE of 17.79 % and greatly enhanced operational lifetime. The temperature‐dependent and transient EL spectroscopies demonstrate the electrophosphorescence attribute of 3,2‐PIC‐XT. These non‐doped OLEDs are the best devices based on purely organic RTP materials reported so far. [ABSTRACT FROM AUTHOR]

Integrating aggregation‐induced emission (AIE) into thermally activated delayed fluorescence (TADF) emitters holds great promise for the advancement of highly efficient organic light emitting diodes (OLEDs). Despite recent advancements, a thorough comprehension of the underlying mechanisms remains imperative for the practical application of such materials. In this work, we introduce a novel approach aimed at modulating the TADF process by manipulating dynamic processes in excited states through aggregation effect. Our findings reveal that aggregation not only enhances both prompt and delayed fluorescence simultaneously but also imposes constraints on molecular reorientation. This constraint reinforces spin‐orbit coupling and reduces the energy gap between singlets and triplets. These insights deepen our understanding of the fundamental mechanisms governing the aggregation effect on TADF materials and provide valuable guidance for the design of high‐efficiency photoluminescent materials. [ABSTRACT FROM AUTHOR]

The lack of a bandgap in stanene severely limits its outstanding characteristics in optoelectronic devices. Using first-principles calculations, we systematically investigate the effects of full hydrogenation and shear deformation on the electronic structure and optical properties of stanene. Hydrogenation exerts a remarkable impact on electronic structure of stanene, enabling surface state transition from quasi-metallic to semiconducting. Shear degrades the structural stability of full-hydrogenated stanene (FHstanene). FHstanene exhibits a tunable bandgap of 1.327 eV, which can be further reduced to 0.719 eV through shear deformation. The presence of spin-orbit coupling (SOC) induces band splitting in FHstanene. The maximum optical absorption of FHstanene occurs at 291 nm, while the reflectance peak is observed at 449 nm. The variation in bandgap due to deformation results in a redshift in the absorption coefficient and reflectance, and shear deformation increases the reflectance of FHstanene. These findings broaden the application prospects of stanene in novel nano-optoelectronic devices. [ABSTRACT FROM AUTHOR]

We consider the ground state of Rydberg-dressed Bose gas with spin–orbit coupling and confined in a two-dimensional optical lattice. The effects of system's parameters, especially the nonlocal Rydberg interaction and spin–orbit coupling, on the ground-state structure of such a system are explored in full parameter space. It is found that in the absence of spin–orbit coupling, the ground-state structure of the system changes from the initial optical lattice structure to a two-dimensional periodic one with the cell size decreasing with the strength of Rydberg interaction. In the presence of spin–orbit coupling, both the phase and the internal structure of unit cell show strong dependence on the strength of spin–orbit coupling. Finally, the strong interacting gas is also considered. [ABSTRACT FROM AUTHOR]

In graphene on transition metal dichalcogenides, two types of spin–orbit coupling (SOC)—Rashba and spin–valley Zeeman SOCs—can coexist that modify graphene's electronic band differently. Herein, it is shown that the Landau levels (LLs) are also affected by these SOCs distinctively enough to estimate their relative strengths from the Landau fan diagram. A simple theoretical model is used to calculate the LL spectra of graphene for different SOC strengths, revealing that when the total SOC is strong enough (i.e., when it is comparable to the half of the energy gap between the LLs of an intrinsic graphene), the corresponding LLs will split and cross with others depending sensitively on the relative strengths of the SOC terms. To demonstrate how one can use it to estimate the relative SOC strengths, the four key features that are well separated from the complex background are first identified and compared with experiment to show that in the sample investigated, the Rashba SOC is stronger than the spin–valley Zeeman SOC consistent with other spectroscopic measurements. The study therefore provides a simple and practical strategy to analyze the LL spectrum in graphene with SOC before carrying out more in‐depth measurements. [ABSTRACT FROM AUTHOR]

While considering the appearance of Dirac cones in spin–orbit coupled two-dimensional materials, Young and Kane (Phys Rev Lett 115:126803, 2015) have found that, in the absence of other symmetries, spatial-, time-reversal and vertical glide plane (or horizontal screw rotation) symmetry give four-fold degenerate Dirac point at the time-reversal invariant momentum along the fractional translation. Here we show in which cases additional symmetries lead to Dirac line instead of Dirac cone in the band structure. We found three centrosymmetric, non-symmorphic layer double groups with line-like degeneracies instead of nodal points. We show that besides these Dirac lines, no other band contacts occur, including the accidental ones. Our results are illustrated using a tight binding example arising from s-orbitals on two atoms in the primitive cell. Finally, we discussed ways towards realistic materials where such features in the electronic dispersion are expected to appear. [ABSTRACT FROM AUTHOR]

We investigated the ground-state properties of a two-dimensional Fermi superfluid with an anisotropic spin-orbit coupling (SOC) using the path-integral field theoretical method. Within the framework of mean-field theory, we obtained the condensed fraction, including contributions from both singlet and triple pairing fields. We found that for small interaction parameters and large anisotropic parameters, the total condensed fraction changes non-monotonically when increasing the strength of SOC and has a global maximum. But this feature disappears when decreasing the anisotropic parameter and increasing the interaction parameter. However, the condensed fraction always decreases with increasing anisotropic parameters. Because of the anisotropy of the SOC, the superfluid fraction becomes a tensor. We obtained the superfluid fraction tensor by deriving the effective action of the phase field of the order parameter. Our numerical results show that for small interaction parameters and large anisotropic parameters, the superfluid fraction of the x component ρ x has a minimum as a function of the SOC strength. And this minimum of ρ x disappears when decreasing the anisotropic parameters. In the strong interaction regime, ρ x always decreases with increasing the strength of SOC. While for the y component of the superfluid fraction ρ y , no matter how large the interaction parameters and anisotropic parameters are, it always has a minimum as a function of the SOC strength. As a function of the anisotropic parameter, for strong SOC strength, ρ x < ρ y with ρ x having a minimum. For small SOC parameters, ρ x > ρ y with ρ y developing a minimum only in the weak interaction limit. [ABSTRACT FROM AUTHOR]

We have explored the electronic and optical properties of the stanene–BeO heterostructure using density functional theory (DFT), including van der Waals interaction using the DFT-D3 correction method of Grimme. The heterostructure exhibits a significant band gap opening, with 93 meV (PBE) and 141 meV (HSE06) values. The impact of spin–orbit coupling (SOC) has also been studied, with PBE + SOC exhibiting a band gap of 55 meV and HSE06 + SOC exhibiting a band gap of 71 meV. Using the DFT-1/2 method, various optical parameters of BeO and Sn monolayer and Sn-BeO heterostructure were studied. The results show a strong red shift in the absorption coefficient, extinction coefficient, and reflectivity, with a prominent absorption peak in the near-UV and visible regions. A significant second harmonic generation peak of 8 × 104 pm V−1 was also obtained. The excellent optical properties of the heterostructure indicate its potential for use in future optoelectronic devices. [ABSTRACT FROM AUTHOR]

Bismuth is a well-known semimetal material with strong spin–orbit coupling and has been confirmed to exhibit a larger spin Hall angle in CuBi and PtBi alloys with low Bi-doping concentration. In this study, we investigated perpendicular magnetic anisotropy (PMA) and spin–orbit torques (SOTs) in Pt/Co/Pt multilayers by inserting a Bi layer with a thickness of 2 nm at the Co/Pt interface. Two types of PMA multilayers, Pt (3 nm)/Co (1 nm)/Pt (5 nm) and Pt (3 nm)/Co (1 nm)/Pt (1 nm), with different spin accumulations, were designed and prepared by varying the top Pt thickness. A significant enhancement of PMA and SOT efficiency is observed in the Pt (3 nm)/Co (1 nm)/Bi (2 nm)/Pt (5 nm) multilayer via a Bi-layer interfacial decoration. However, for the Pt (3 nm)/Co (1 nm)/Bi (2 nm)/Pt (1 nm) multilayers, both PMA and SOT efficiency decrease with decoration of the Bi layer at the Co/Pt interface. Meanwhile, the sign of SOTs changes in the Pt (3 nm)/Co (1 nm)/Pt (5 nm) and Pt (3 nm)/Co (1 nm)/Pt (1 nm) multilayers when introducing a Bi layer. This completely opposite behavior illustrates that the Bi/Pt interface plays an important role in modulating the PMA and SOT efficiency of Pt/Co/Bi/Pt multilayers. Optimizing the alloying of Bi/Pt could be an effective approach to increase the PMA and SOT efficiency of Pt/Co/Bi/Pt multilayers. [ABSTRACT FROM AUTHOR]

We consider the problem of the magnetization dynamics of a nanosized ferromagnetic sample caused by the spin–orbit interaction of electrons arising in the field of an incident electromagnetic wave. We discuss the case when the frequency of the incident electromagnetic radiation is close to the frequency of the interband transitions. We show that with the use of high-power lasers, this mechanism causes the appearance of a magnetization component perpendicular to the initial magnetization of the sample. This component shows oscillations with a frequency lower than that of incident electromagnetic waves. These dynamics make possible the magnetization reversal of the sample. [ABSTRACT FROM AUTHOR]

The molecular IrF5−, IrF6− anions and M[IrF6] (M=Na, K, Rb, Cs) ion pairs were prepared by co‐deposition of laser‐ablated alkali metal fluorides MF with IrF6 and isolated in solid neon or argon matrices under cryogenic conditions. The free anions were obtained as well by co‐deposition of IrF6 with laser‐ablated metals (Ir or Pt) as electron sources. The products were characterized in a combined analysis of matrix IR spectroscopy and electronic structure calculations using two‐component quasi‐relativistic DFT methods accounting for spin‐orbit coupling (SOC) effects as well as multi‐reference configuration‐interaction (MRCI) approaches with SOC. Inclusion of SOC is crucial in the prediction of spectra and properties of IrF6− and its alkali‐metal ion pairs. The observed IR bands and the computations show that the IrF6− anion adopts an Oh structure in a nondegenerate ground state stabilized by SOC effects, and not a distorted D4h structure in a triplet ground state as suggested by scalar‐relativistic calculations. The corresponding "closed‐shell" M[IrF6] ion pairs with C3v symmetry are stabilized by coordination of an alkali metal ion to three F atoms, and their structural change in the series from M=Na to Cs was proven spectroscopically. There is no evidence for the formation of IrF7, IrF7− or M[IrF7] (M=Na, K, Rb, Cs) ion pairs in our experiments. [ABSTRACT FROM AUTHOR]

Comprehensive Summary Room‐temperature phosphorescence (RTP) materials have experienced rapid development due to their potential in organic light‐ emitting diode, information security, bioimaging, etc. However, the design of chiral organic phosphors with circularly polarized RTP (CPP) property remains a formidable challenge. Here, we introduce a chiral perturbation approach using a combination of chiral binaphthol and phenoselenazine derivative to achieve CPP. The photoactivated CPP in polystyrene (PS) film demonstrates a luminescence dissymmetry factor (glum), emission efficiency, and RTP lifetime up to 9.32 × 10–3, 27.0%, and 40.0 ms, respectively. The remarkable sensitivity of PS film to oxygen and temperature enables the adjustable emission colors, ranging from green to offwhite and blue under varying conditions. The doping systems, utilizing hosts of triphenylphosphine and 9‐phenylcarbazole, demonstrate an extended CPP lifetime of 85.9 ms and exhibit a persistent mechanoluminescence property with low pressure response threshold as low as 0.15 N. The information security provided by this CPP material was attained via the using of diverse emission colors and afterglow generated by distinct UV irradiation times and host materials. Alternately, it can also be achieved by observing different emission patterns using R‐ and L‐polarizer. The research has presented a reliable approach for producing CPP materials with high emission efficiency and glum. [ABSTRACT FROM AUTHOR]

In this paper, we study-induced spin–orbit coupling (SOC) in one-dimensional ultracold quantum gases composed of atoms of different species. One species is subjected to an equal combination of Rashba and Dresselhaus SOC generated by Raman transition. The two species interact with each other through spin-independent and spin-exchange contact interactions. The spin-exchange interaction introduces a locking pattern of the momentum and spin degrees of freedom for the species without direct SOC. For small spin-independent interactions, the two species overlap and the induced SOC is effective. For large spin-independent interactions, however, the two species keep separate from each other and the induced SOC is negligible. We propose to generate inhomogeneous SOC by exploiting density engineering technique applied to the directly spin–orbit coupled Bose–Einstein condensate. When the effective potential is of Gaussian type, the single-particle eigenenergies and eigenstates are calculated by exact diagonalization method. For general cases, mean-field ground states are obtained by numerically searching for the minimum of energy functional. With the density engineering technique, it is possible to produce hybrid structures of plane wave, stripe and/or zero-momentum phases. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Kasha's exciton model proposes that T1 energy levels of organic compounds are insensitive to molecular aggregation and microenvironment change because of negligible small transition dipole moments of T1 states. This model holds true in most organic systems till now. Here we report the fabrication of twisted organic phosphors with intramolecular charge transfer characters and flexible molecular structures. When doped into different organic matrices, the twisted phosphor adopts different conformation, exhibits distinct phosphorescence colors and T1 energy levels, which violates Kasha's exciton model in organic system. Given that the change of phosphorescence colors and maxima can be readily distinguished by human eyes and conventional instrument, the twisted phosphors would be exploited as a new type of molecular probe, which would exhibit potential application in optical sensing and stimuli‐responsive systems. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the spin–orbit coupling of F = 1 dipolar Bose–Einstein condensates in a quasi-one-dimensional trap by solving the mean field Gross–Pitaevskii equation. We focus on the two phases, ferromagnetic and antiferromagnetic. For the former, we find that the spin echo signal emerges gradually as the spin–orbit coupling strength increases, which favors miscibility in density profile. The dipolar interaction plays a tiny role in the spin dynamics process, the qualitative behavior remains almost unchanged. Nevertheless, for the antiferromagnetic phase, the physical picture greatly changes. The spin echo signal abruptly increases with the increase in spin–orbit coupling strength, and the density structure exhibits phase separation. With the emergence of dipolar interaction, the spin echo signal vanishes, and the evolution of the three components is ruleless. Meanwhile, the condensate deviates from the property of phase separation. Also, we analyze the effect of the number of atoms on spin dynamics. It is obvious that the reduction of atoms increases the number of spin echo signals for the ferromagnetic phase regardless of the nature of dipolar interaction. In addition, for the antiferromagnetic phase, such a decrease gives rise to the disappearance of the spin echo signal in the absence of dipolar interaction, and its influence is small when dipolar interaction is added. [ABSTRACT FROM AUTHOR]

Optoelectronic and spinoptronic technologies benefit from flexible and tunable coherent light sources combining the best properties of nano- and material-engineering to achieve favorable properties such as chiral lasing and low threshold nonlinearities. In this work we demonstrate an electrically wavelength- and polarization-tunable room temperature polariton laser due to emerging photonic spin–orbit coupling. For this purpose, we design an optical cavity filled with both birefringent nematic liquid crystal and an inorganic perovskite. Our versatile growth method of single CsPbBr3 inorganic perovskite crystals in polymer templates allows us to reach strong light–matter coupling and pump-induced condensation of exciton–polaritons resulting in coherent emission of light. The sensitivity of the liquid crystal to external voltage permits electrical tuning of the condensate energy across 7 nm; its threshold power, allowing us to electrically switch it on and off; and its state of polarization sweeping from linear to locally tilted circularly polarized emission. [ABSTRACT FROM AUTHOR]

We report a joint spectroscopic and theoretical study probing spin-orbit coupling (SOC) in a variety of molecular complexes between an iodine atom and a ligand (L) with L ranging from Ar, HF to formic/acetic acids, and glycine/N-methylated glycine derivatives. Cryogenic photoelectron spectroscopy of L·I- (L=HCOOH, CH3COOH) reveals three distinct peaks, identified as three SOC states, denoted as X(1/2), A(3/2), and B(l/2) for the corresponding neutrals. The X and A separation ΔEXA is measured to be 0.10 eV for both, whereas the X and B gap ΔEXB is 0.98 and 0.97 eV for formic and acetic acid, respectively. These new ΔEXA values are compared with the previously reported values for the molecular complexes L·I· with L=Ar, HF, glycine, and A-methylated glycines. All together these complexes encompass a diversity of intermolecular interactions, from van der Waals to weak and strong hydrogen bonding. While the ΔEXB remains similar, the ΔEXA is shown to be extremely sensitive to the type of ligands and interactions, spanning from 5 meV to 150 meV. High-level relativistic quantum calculations including explicit SOC formulism nicely reproduce all experimental SOC splitting. A direct correlation between the magnitude of ΔEXA with the intermolecular interaction strength or bond distance of the neutral complexes—the stronger interaction (shorter bond length), the greater splitting, is established. [ABSTRACT FROM AUTHOR]

Studies toward transition metals in negative oxidation states are much less explored compared to those in zero or positive oxidation states. In this study, we present the synthesis and reactivity studies of an Fe(‐II) carbonyl dianion (3) featuring an appended Lewis base, [(L)Fe(CO)3]2− (L=Ph2PCH2CH2NMe2). Unlike the well‐known reactivity of [Fe(CO)4]2− with common electrophiles (E+) which typically forms [(E)2Fe(CO)4], 3 reacted with 2 equiv. of Ph3SnCl to afford a mixture of two products: one being an Fe(II) bis(triphenylstannyl) product (4), and the other an Fe stannylene product (5). Further insights into the reactivity of 3 was elucidated through its reactions with 2 equiv. of Cy3SnCl or Me3SiCl, producing an Fe(II) bis(tricyclohexylstannyl) product (8) and a zwitterionic complex (11), respectively, the latter emerging via THF ring‐opening. Intermediates generated from reactions of 3 with 1 equiv. of each electrophile were isolated to shed light on the reaction mechanisms, highlighting the influence of appended Lewis base on the reactivity of metal carbonyl dianions, especially the generation of the novel stannylene complex 5. The electronic structure of this paramagnetic stannylene complex was also investigated by computational studies. [ABSTRACT FROM AUTHOR]

Controlling the formation of photoexcited triplet states is critical for many (photo)chemical and physical applications. Here, we demonstrate that a permanent out‐of‐plane distortion of the benzothioxanthene imide (BTI) dye promotes intersystem crossing by increasing spin‐orbit coupling. This manipulation was achieved through a subtle chemical modification, specifically the bay‐area methylation. Consequently, this simple yet efficient approach expands the catalog of known molecular engineering strategies for synthesizing heavy atom‐free, dual redox‐active, yet still emissive and synthetically accessible photosensitizers. [ABSTRACT FROM AUTHOR]

Spin–orbit coupling in nanoscale optical fields leads to the emergence of a nontrivial spin angular momentum component, transverse to the orbital momentum. In this study, we initially investigate how this spin–orbit coupling effect influences the dynamics in gold monomers. We observe that localized surface plasmon resonance induces self-generated transverse spin, affecting the trajectory of the nanoparticles as a function of the incident polarization. Furthermore, we investigate the spin–orbit coupling in gold dimers. The resonant spin momentum distribution is characterized by the unique formation of vortex and anti-vortex spin angular momentum pairs on opposite surfaces of the nanoparticles, also affecting the particle motion. These findings hold promise for various fields, particularly for the precision control in the development of plasmonic thrusters and the development of metasurfaces and other helicity-controlled system aspects. They offer a method for the development of novel systems and applications in the realm of spin optics. [ABSTRACT FROM AUTHOR]

Singlet dioxygen has been widely applied in different disciplines such as medicine (photodynamic therapy or blood sterilization), remediation (wastewater treatment) or industrial processes (fine chemicals synthesis). Particularly, it can be conveniently generated by energy transfer between a photosensitizer's triplet state and triplet dioxygen upon irradiation with visible light. Among the best photosensitizers, substituted zinc(II) phthalocyanines are prominent due to their excellent photophysical properties, which can be tuned by structural modifications, such as halogen‐ and chalcogen‐atom substitution. These patterns allow for the enhancement of spin‐orbit coupling, commonly attributed to the heavy atom effect, which correlates with the atomic number (Z ${Z}$) and the spin‐orbit coupling constant (ζ ${\zeta }$) of the introduced heteroatom. Herein, a fully systematic analysis of the effect exerted by chalcogen atoms on the photophysical characteristics (absorption and fluorescence properties, lifetimes and singlet dioxygen photogeneration), involving 30 custom‐made β‐tetrasubstituted chalcogen‐bearing zinc(II) phthalocyanines is described and evaluated regarding the heavy atom effect. Besides, the intersystem crossing rate constants are estimated by several independent methods and a quantitative profile of the heavy atom is provided by using linear correlations between relative intersystem crossing rates and relative atomic numbers. Good linear trends for both intersystem crossing rates (S1‐T1 and T1‐S0) were obtained, with a dependency on the atomic number and the spin‐orbit coupling constant scaling as Z0.4 ${{Z}^{0.4}}$ and ζ0.2 ${{\zeta }^{0.2}}$ , respectively The trend shows to be independent of the solvent and temperature. [ABSTRACT FROM AUTHOR]

Calculations of the contribution from excited electronic states to parameters of the fine structure of the ground electronic state of an OH radical are made in the framework of perturbation theory (Van Vleck contact transformations). The potential energy functions of the electronic states and required matrix elements of spin-orbit and electron-rotation coupling are found from first principles. It is shown that repulsive (unbound) excited electronic states play a crucial role in the dependence of parameters of the fine structure of the ground state on the magnitude of the vibrational excitation. [ABSTRACT FROM AUTHOR]

Quantum phenomena, including entanglement, superposition, tunneling, and spin–orbit interactions, among others, are foundational to the development of recent innovations in quantum computing, teleportation, encryption, sensing, and new modalities of electronics, such as spintronics, spin-orbitronics, caloritronics, magnonics, twistronics, and valleytronics. These emerging technologies provide disruptive influences to global commercial markets. These remarkable advances in quantum technologies are nearly always enabled by the discovery of materials and their quantum behaviors. Such advances are governed by quantum principles that are strongly influenced by environmental, physical, topological, and morphological conditions such as very small length scales, short time durations, ultrahigh pressures, ultralow temperatures, etc., which lead to quantum behaviors that manifest as quantum tunneling, entanglement, superpositioning, superfluidity, low-dimensional, high-temperature and high-pressure superconductivity, quantum fluctuations, Bose–Einstein condensates, topological effects, and other phenomena that are not yet fully understood nor adequately explored. Here, we provide a review of quantum materials developed up to 2023. Remarkable advances in quantum materials occur daily, and therefore, by the time of publication, new and exciting breakthroughs will have occurred that are regrettably not covered herein.

By means of highly accurate ab initio and dynamical calculations, we identify a suitable laser cooling candidate that contains a transition metal element, namely zinc monohydride (ZnH). The internally contracted multireference configuration interaction method is employed to compute the five lowest-lying Λ-S states of ZnH with the spin-orbit coupling effects included, and very good agreement is obtained between our calculated and experimental spectroscopic data. Our findings show that the position of crossing point of the A2Π and B2Σ+ states of ZnH is above the v′ = 2 vibrational level of the A2Π state indicating that the crossings with higher electronic states will have no effect on laser cooling. Hence, we construct a feasible laser-cooling scheme for ZnH using five lasers based on the A2Π1/2 → X2Σ+1/2 transition, which features a large vibrational branching ratio R00 (0.8458), a large number of scattered photons (9.8 × 103) and an extremely short radiative lifetime (64 ns). The present work demonstrates the importance of electronic state crossings and spin-orbit couplings in the study of molecular laser cooling.

The electron-phonon (el-ph) and phonon-phonon interactions play a key role in determining electronic and thermal transport properties, respectively, in promising two-dimensional (2D) semiconductor devices. In this study, we investigated el-ph interactions using Wannier-Fourier interpolation method and renormalized phonon scattering considering finite-temperature effects in Bi2TeSe2 monolayer. The results show that the optical phonon modes dominate the carrier scattering, where level repulsion induced by crystal field splitting and spin-orbit coupling (SOC) effect effectively suppresses intervalley scattering, leading to high hole mobility. Moreover, the strong anharmonicity in Bi2TeSe2 monolayer results in the temperature-dependent softening of its optical phonons, along with a corresponding variation in interatomic force constants (IFCs). As a result, the lattice thermal conductivity is remarkably low and exhibits weak temperature dependence. Finally, the predicted dimensionless thermoelectric figure of merit exceeds unity in the range of 200–800 K, indicating the potential of Bi2TeSe2 monolayer for thermoelectric applications. This work provides new insights into the elimination of intervalley scattering by crystal field splitting and SOC effects, and paves the way for the evaluation of thermoelectric properties of materials with complex scattering mechanisms and strong anharmonicity.

First-principles calculations incorporating spin-orbit coupling are presented for a multiferroic material as a ferromagnetic/ferroelectric junction. We simulate the interface effect that cannot be described by the single-phase bulk. The in-plane uniaxial magnetic-anisotropy of Co2FeSi is observed when the ferroelectric domain is polarized parallel to the interface, whereas the magnetic anisotropy is significantly different in the plane for the electrical polarization perpendicular to the interface. While the single-phase effect dominates the main part of the modulation of the magnetic anisotropy, symmetry breaking due to the interfacial effect is observed in the ferromagnetic ultrathin films. The origin of the modulated magnetic-anisotropy can be attributed to the shifting of specific energy bands in Co2FeSi when the ferroelectric domain is modified.

ABSTRACTThis concise review aims to provide a summary of the most relevant recent experimental and theoretical results for solitons, i.e. self-trapped bound states of nonlinear waves, in two- and three-dimensional (2D and 3D) media. In comparison with commonly known one-dimensional solitons, which are, normally, stable modes, a challenging problem is the propensity of 2D and 3D solitons to instability, caused by the occurrence of the critical or supercritical wave collapse (catastrophic self-compression) in the same spatial dimensions. A remarkable feature of multidimensional solitons is their ability to carry vorticity; however, 2D vortex rings and 3D vortex tori are subject to a strong splitting instability. Therefore, it is natural to categorize the basic results according to physically relevant settings which make it possible to stabilize fundamental (non-topological) and vortex solitons against the collapse and splitting, respectively. The present review is focused on schemes that were recently elaborated in terms of Bose-Einstein condensates and similar photonic setups. These are two-component systems with spin-orbit coupling, and ones stabilized by the beyond-mean-field Lee-Huang-Yang effect. The latter setting has been implemented experimentally, giving rise to stable self-trapped quasi-2D and 3D quantum droplets. Characteristic examples of stable three-dimensional solitons: a semi-vortex (top) and mixed-mode (bottom) modes in the binary Bose-Einstein condensate, stabilized by the spin-orbit coupling.

An ideal thermoelectric material requires the multi-valley and strong dispersion band structure, for relieving the competition between thermopower and electrical conductivity, whereas the two features barely coexist in natural compounds. Here, the significantly improved thermoelectric performance in n-type PbSe-xAgSbS2 with the purposefully renormalized conduction band structure is reported. It is shown that the strong spin-orbit coupling effect splits the single valley at "L" point into three individuals delicately, as the Dirac point is shifted away from the high symmetry point by the decreasing lattice constant. Compared with the common PbSe-based compounds, the renormalized system exhibits a range of distinctive properties, such as the 2-3 times larger band gap, 5-10 times lower optimal carrier concentration, and weakly temperature-dependent Seebeck coefficient. Owing to the achieved giant band convergence and the low thermal conductivity, a high peak zT of 1.75 at 850 K and an outstanding average zT of 1.04 are obtained. Furthermore, the mechanical property and thermal stability of PbSe are considerably improved for the introduced high entropy effect and lattice shrinkage. This study reveals the remarkable impact of spin-orbit coupling on thermoelectric performance, and suggests that the optimized PbSe material holds great promise for practical applications. [ABSTRACT FROM AUTHOR]

Strong spin–orbit coupling (SOC) in iridates has long been predicted to lead to exotic electronic and magnetic ground states. Ba 2 YIr O 6 (BYIO) has attracted particular attention due to the expectation of a J eff = 0 state for Ir 5 + ions under the j j -coupling scheme. However, controversies surround the actual realization of this state, as finite magnetic moments are consistently observed experimentally. We present a multi-physics study of this system by progressively introducing nonmagnetic Sb 5 + ions in place of Ir 5 + ( Ba 2 YIr ​ 1 − y Sb ​ y O ​ 6 , BYISO). Despite similar charge and ionic radii, Sb ​ 5 + doping appears highly inhomogeneous, coexisting with a fraction of nearly pure BYIO regions, as confirmed by X-ray diffraction (XRD). This aligns with observations in related compounds. While inhomogeneity creates uncertainty, the doped majority phases offer valuable insights. It is relevant that the inclusion of even small amounts of Sb ​ 5 + (10–20%) leads to a rise in magnetization. This strengthens our previous suggestion that magnetic Ir ions form dynamic singlets in BYIO, resulting in a near-nonmagnetic background. The observed moment enhancement with nonmagnetic doping supports the breakdown of these singlets. Furthermore, the magnetization steadily increases with an increasing Sb ​ 5 + content, contradicting the anticipated approach towards the J eff = 0 state with increased SOC due to reduced hopping between Ir ​ 5 + ions. This reinforces the presence of individual Ir ​ 5 + moments. Overall, our findings suggest that Ba ​ 2 YIrO ​ 6 might not possess sufficiently strong SOC to be solely described within the j j -coupling picture, paving the way for further investigation. [ABSTRACT FROM AUTHOR]

A sample with the spin Hall effect causes spin-orbit coupling to induce spin-polarized electrons that accumulate inverse signals on either side of the sample. In this study, a multiterminal device was fabricated using a tantalum Hall bar and a spin injector of the permalloy nanowire to detect inverse Hall effect signals. This device can read the different spin Hall signals emitted from the magnetic state of the permalloy wire. Our results reveal that the different magnetic states of the permalloy wire cause an asymmetric shift of the inverse spin Hall voltage and also display various signals at opposite directions of currents. As the input current increases, the voltage also exhibits nonlinear growth. This indicates that the inverse spin Hall signals are affected by the magnetic state of the permalloy wire and the input current direction. This also indicates that the inverse spin Hall signals from the multiterminal device can inspire the design of the sensor for detecting spin electrons and neuron-like magnetization states. [ABSTRACT FROM AUTHOR]

Metal halide perovskites (MHPs) exhibit strong spin‐orbit coupling and structural inversion asymmetry, making them ideal for testbeds of Rashba effects and for use in spin‐related optoelectronic and spintronic applications. However, the Rashba band splitting is mainly observed in bulk MHPs so far and is rarely observed in thin films. In this study, a direct observation of Rashba band splitting in MHP thin films at room temperature is reported. By employing a silicone rubber substrate with a high thermal expansion coefficient, the out‐of‐plane tensile strain significantly reduces the activation energy of ion migration in these thin films and leads to a considerable amount of point defects. These point defects disrupt the inversion symmetry and ultimately give rise to the Rashba band splitting. These findings open up new possibilities for manipulating Rashba effects in MHP thin films through device engineering. [ABSTRACT FROM AUTHOR]

Recently, surface‐hopping ab initio molecular dynamics (SH‐AIMD) simulations have come to be used to discuss the mechanisms and dynamics of excited‐state chemical reactions, including internal conversion and intersystem crossing. In dynamics simulations involving intersystem crossing, there are two potential energy surfaces (PESs) governing the motion of nuclei: PES in a spin‐pure state and PES in a spin‐mixed state. The former gives wrong results for molecular systems with large spin‐orbit coupling (SOC), while the latter requires a potential gradient that includes a change in SOC at each point, making the computational cost very high. In this study, we systematically investigate the extent to which the magnitude of SOC affects the results of the spin‐pure state‐based dynamics simulations for the hydride MH2 (M = Si, Ge, Sn, Pb) by performing SH‐AIMD simulations based on spin‐pure and spin‐mixed states. It is clearly shown that spin‐mixed state PESs are indispensable for the dynamics simulation of intersystem crossing in systems containing elements Sn and Pb from the fifth period onward. Furthermore, in addition to the widely used Tully's fewest switches (TFS) algorithm, the Zhu‐Nakamura (ZN) global switching algorithm, which is computationally less expensive, is applied to SH for comparison. The results from TFS‐ and ZN‐SH‐AIMD methods are in qualitative agreement, suggesting that the less expensive ZN‐SH‐AIMD can be successfully utilized to investigate the dynamics of photochemical reactions based on quantum chemical calculations. [ABSTRACT FROM AUTHOR]

The Lee-Huang-Yang（LHY）correction refers to the self trapping state in the Bose Einstein condensates, which is stabilized through effective self repulsion caused by quantum fluctuations around the mean field（MF）state. However, the LHY correction may affect the ground state of bright solitons in Bose Einstein condensates, leading to a certain range of applicability for the experimental solution of bright solitons. This study utilized variational approximation and numerical simulation methods based on the Gross Pitaevskii equation. By incorporating LHY corrections to the ground state models of quasi one-dimensional Bose Einstein condensates with single and two components, the experimental and numerical simulation solutions of the two systems were calculated. The calculation shows that for quasi one-dimensional single component and two component Bose Einstein condensates with LHY terms, good static approximate solutions can be obtained through the variational method under certain conditions for the LHY coefficient G of the system. The research in this article provides theoretical support for obtaining the ground state analytical solutions of single and two component Bose Einstein condensates with LHY terms in the quasi one-dimensional case, and provides assistance for future research on the properties and physical connotations of the system. [ABSTRACT FROM AUTHOR]