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Introducing post-transition metal cations is an excellent strategy for enhancing optical properties. This paper focuses on four isomers, namely the X2PO4I (X = Pb, Sn, Ba, and Sr) series. For the first time, the paper's attention is paid to the changes in electronic structure, as well as refractive indices and birefringence, with and without the inclusion of spin–orbit effects in this series. The first-principles results show that spin–orbit effects of the 5p and 6p states found in these compounds lead to splitting of the bands, narrowing of the band gap, enhancement of the lone-pair stereochemistry, and enhancement of the refractive indices and birefringence. Moreover, a comparison of the lone-pair electron phosphates, X2PO4I (X = Pb and Sn), and the isomeric alkaline earth metal phosphates, X2PO4I (X = Ba and Sr), reveals that changes in the band structure have a greater effect on the enhancement of the birefringence than the slight enhancement of the lone-pair stereochemical activity. This study has important implications for a deeper understanding of the optical properties of crystals and the design of novel optical materials. [ABSTRACT FROM AUTHOR]

We investigate the quantum phases and phase transitions for spin–orbit coupled two-species bosons with nearest-neighbor (NN) interaction in a two-dimensional square lattice using inhomogeneous dynamical Guztwiller mean-field method. Under the effect of spin–orbit coupling and NN interaction, we uncover a rich variety of different magnetic supersolid (SS) phases. In the presence of intraspecies NN interaction, the phase diagram exhibits the phase-twisted double-checkerboard SS (PT-DCSS) and phase-striped double-checkerboard SS (PS-DCSS) phases. For both intra- and interspecies NN interactions, apart from the phase-twisted lattice SS (PT-LSS) and phase-striped lattice SS (PS-LSS) phases, some nontrivial SS phases with interesting properties occur. More importantly, we find that the emergences of these nontrivial SS phases are dependent of the interspecies on-site interaction. To further characterize the SS phases, we also discuss the spin-dependent momentum distributions and magnetic textures. The magnetic textures, such as antiferromagnetic, spiral and stripe orders are shown. Finally, we give the fully analytical insights into the numerical results. [ABSTRACT FROM AUTHOR]

[Display omitted] The realization of spin–orbit-coupled ultracold gases has driven a wide range of research and is typically based on the rotating wave approximation (RWA). By neglecting the counter-rotating terms, RWA characterizes a single near-resonant spin–orbit (SO) coupling in a two-level system. Here, we propose and experimentally realize a new scheme for achieving a pair of two-dimensional (2D) SO couplings for ultracold fermions beyond RWA. This work not only realizes the first anomalous Floquet topological Fermi gas beyond RWA, but also significantly improves the lifetime of the 2D-SO-coupled Fermi gas. Based on pump–probe quench measurements, we observe a deterministic phase relation between two sets of SO couplings, which is characteristic of our beyond-RWA scheme and enables the two SO couplings to be simultaneously tuned to the optimum 2D configurations. We observe intriguing band topology by measuring two-ring band-inversion surfaces, quantitatively consistent with a Floquet topological Fermi gas in the regime of high Chern numbers. Our study can open an avenue to explore exotic SO physics and anomalous topological states based on long-lived SO-coupled ultracold fermions. [ABSTRACT FROM AUTHOR]

Systematic quantum chemical calculations were performed for the ground and a number of low-lying electronically excited doublet and quartet states of the rubidium trimer molecule. The obtained potential energy surfaces (PES), spin-orbit couplings (SOC) and electronic transition dipole moments (ETDM) can be useful for optimizing paths for laser synthesis, cooling and manipulation of stable ensembles of Rb3 molecules at ultralow temperatures. Ab initio calculations of the electronic structure of the homonuclear Rb3 molecule, in linear, isosceles triangle and equilateral triangle geometries, were performed using the multi-reference configuration interaction method, taking into account single and double excitations (M-R‑CISD) and with explicit dynamic correlation of only the three valence electrons. The structure of each atom was approximated using a nine-electron effective core potential (ECP28MDF), and molecular orbitals (MOs) were optimized using the spin averaged (over doublet and quartet states) multi-configuration self-consistent field (SA-CASSCF) method. Core–valence correlations between twenty-four subvalence electrons located on doubly occupied MOs and three valence electrons were implicitly taken into account using a one-electron angular momentum-independent Müller–Mayer core polarization potential (CPP). As a result of topological investigations at over 35 000 points, two dimensional PES, SOC, and ETDM functions were obtained and the geometric parameters Rb3 were found at which the most intense vertical transitions and the maximum influence of the SOC are expected. [ABSTRACT FROM AUTHOR]

Organic room‐temperature phosphorescence (RTP) from triplet excitons has shown great potential for biological imaging and sensing, but these applications in aqueous environments are often limited by the moisture‐mediated phosphorescence quenching. Water‐induced enhancement of RTP can overcome this limitation, but the underlying mechanism remains unclear. This study focuses on two control prototypes CT and CTW, composed of trimesic acid (TMA, guest) and cyanuric acid (CA, host), while CTW introduces 20 wt.% water to CT, leading to enhanced RTP. Theoretical calculations demonstrate that the molecular conformation of TMA manipulated by intermolecular interactions governs the RTP property of aggregates. From CT to CTW, the TMA tends to a more coplanar geometry due to the decreased values in the span of deviation from plane. This conformational change not only increases the spin‐orbit coupling (SOC) of S1→Tn, thereby accelerating the intersystem crossing process and radiative transition for promoting RTP efficiency, but also reduces the SOC of T1→S0, suppressing the non‐radiative transition to prolong RTP lifetime. Exciton dynamics reproduce the prolonged RTP lifetime from CT to CTW in experiments, which is dominated by the SOC, rather than the electron‐vibration coupling. The findings offer novel insights for developing water‐doped materials with improved RTP performance. [ABSTRACT FROM AUTHOR]

Half-metallic ferromagnetic Heusler alloys attracted much attention in the last few decades due to their significant physical properties as well as its potential applications in spintronic devices. To explore and predict the various physical properties of Co-based Heusler alloy, Co2MnSi (CMS), First principles calculations are of interest and has been used in the present study. Optimized E–V curves represent that CMS alloy is most stable in its magnetic L21 structural phase. The electronic charge density plot represents the ionic bonding along with co-valent character for the compound. DOS and BS calculations shows 100% spin polarization at Fermi level (EF) which confirms the half metallic character of the compound. DOS exhibited the prominent role of Co-3d and Mn-3d electronic states along with Si-2p electronic states. Estimated magnetic moment of Co2MnSi Heusler alloy was found to be ~ 5μB per f. u. which is in line with the Slater-Pauling behaviour. Dynamical stability of Co2MnSi Heusler alloy has also been verified by the phonon dispersion curves which revealed that compound is dynamically stable. Additionally, the physical properties have also been explored as a consequence of SOC and significant changes in electronic and optical properties were observed. The observed significant results of electronic, magnetic, and optical properties of CMS Heusler alloy makes it promising towards potential application in optical and spintronic devices. [ABSTRACT FROM AUTHOR]

Purpose: The 1:1 spin-orbit resonance phenomenon is widely observed in binary asteroid systems. We aim to investigate the intrinsic dynamic mechanism behind the phenomenon under the coupled influence of the secondary's rotation and orbital motion. Methods: The planar sphere–ellipsoid model is used to approximate the synchronous binary asteroid. The Lindstedt–Poincaré method is applied on the spin-orbit problem to find its explicit quasi-periodic solution. Results: Numerical simulations demonstrate that analytical solutions truncated at high orders are accurate enough to describe the orbital and rotational motions of the synchronous binary asteroid. With the help of the solution, we are able to identify in a more accurate way the stable region for the synchronous state by using the Lyapunov characteristic exponent. Moreover, the resonances that determine the boundary of the stability region are identified. Conclusion: The stable synchronous state requires a small eccentricity e of the mutual orbit but permits a large libration angle θ of the secondary. The anti-correlation of θ and e is confirmed. The stable region for a very elongated secondary is small, which helps explain the lack of such secondaries in observations (see Table 1 in Pravec et al. in Icarus 267:267–295, 2016). Findings of this study provide insights into the inherent dynamics that determine the rotational states of a synchronous binary asteroid. [ABSTRACT FROM AUTHOR]

The equation-of-motion coupled-cluster (EOM-CC) methods with spin-orbit coupling are used to study the low-lying states of . Spectroscopic constants and potential energy curves are mainly calculated using the EOM-CC and the approximate methods named EOM-CC (a) and EOM-CC (b). These two methods which are extended based on EOM-CC by us can reduce the computational effort for ionization potentials (IPs) and electron affinities (EAs) from N6 to N5. N is the system size. The results show that the EOM-CC method can accurately simulate the spectroscopic constants and potential energy curves of the low-lying states of . The EOM-CC (b) approximate method emerges as a favorable and highly agreeable alternative to the EOM-CC approach. [ABSTRACT FROM AUTHOR]

The present review is aimed to understand the Rashba and Dresselhaus effects from the first-principle calculations. A brief overview of first-principle density functional theory (DFT) and its global acceptance have been discussed. The discussions of the Rashba–Dresselhaus splittings, spin textures and understanding the effects from first-principle DFT calculations have been highlighted. Rashba and Dresselhaus effects have gained much attention in recent era for their highly promising applications in spintronics. In the presence of spin-orbit coupling and inherent non-centrosymmetry, while BiTeCl, TiS2Se, rhombohedral CsPbF3 and BiCoO3 compounds show large values of Rashba parameter ( α R) of ∼ 1. 9 0 , 1.10, 1.05 and 0.74 eVÅ, respectively, the single-layered semiconductor nanostructure InSb, rhombohedral BiFeO3 and Ag2BiO3 systems however depict promising values of Dresselhaus parameter ( α D) of ∼ 2. 2 0 , 0.50 and 0.15 eVÅ, respectively. The future of Rashba–Dresselhaus effects and their advancements in spintronics have also been enlightened in this paper. We believe that this study will not only help to understand the Rashba–Dresselhaus effects from first-principle calculations, but can also augment their applications in next generation spintronic devices. [ABSTRACT FROM AUTHOR]

Van Hove singularities in proximity to the Fermi level promote electronic interactions and generate diverse competing instabilities. It is also known that a nontrivial Berry phase derived from spin–orbit coupling can introduce an intriguing decoration into the interactions and thus alter correlated phenomena. However, it is unclear how and what type of new physics can emerge in a system featured by the interplay between van Hove singularities (VHSs) and the Berry phase. Here, based on a general Rashba model on the square lattice, we comprehensively explore such an interplay and its significant influence on the competing electronic instabilities by performing a parquet renormalization group analysis. Despite the existence of a variety of comparable fluctuations in the particle–particle and particle-hole channels associated with higher-order VHSs, we find that the chiral p ± i p pairings emerge as two stable fixed trajectories within the generic interaction parameter space, namely the system becomes a robust topological superconductor. The chiral pairings stem from the hopping interaction induced by the nontrivial Berry phase. The possible experimental realization and implications are discussed. Our work sheds new light on the correlated states in quantum materials with strong spin–orbit coupling (SOC) and offers fresh insights into the exploration of topological superconductivity. [ABSTRACT FROM AUTHOR]

The emergence of robust surface electronic states in topological insulators such as bulk Sr3PbO inverse‐perovskite makes them suitable candidates for spintronic devices and solid‐state quantum computers. Herein, the atomic structure, surface energetics, and electronic properties of Sr3PbO inverse‐perovskite Sr2O (SO)‐terminated and SrPb‐terminated (001) surfaces are examined using density functional theory. A comparison of the computed structural properties of SO‐termianted and SrPb‐terminated (001) surfaces reveals maximum surface rumpling and changes in interlayer distances for the SrPb‐terminated surface of Sr3PbO. However, the calculated surface energies indicate that both SO‐termianted and SrPb‐terminated (001) surfaces of Sr3PbO are energetically feasible, indicating that these surfaces can coexist in a polycrystalline sample of this material. Due to the presence of Pb in Sr3PbO, a comprehensive examination of the electronic structure of bulk and supercell slab structures of Sr3PbO by taking spin–orbit coupling effects into consideration is conducted. Noninsulating nature of electronic structure for the two possible (001) terminations of Sr3PbO is found. The domination of Pb‐6p states at the Fermi energy and the hole screening observed at the SrPb‐terminated surface of Sr3PbO support the p‐type nature observed in the experiment. [ABSTRACT FROM AUTHOR]

The primary objective of this study is to investigate the influence of spin-orbit coupling and atom type on the electronic, optical, and thermoelectric properties of LuXNi2Sn2 (X = V, Nb, and Ta) double-half Heusler alloys. To achieve this, calculations were performed using the full potential linearized augmented plane wave method within the framework of density functional theory. Both full relativistic and scalar relativistic calculations were employed. The exchange-correlation interactions in this study were modeled using the PBEsol version of the generalized gradient approximation when calculating the structural ground state parameters. For the analysis of electronic, optical, and thermoelectric properties, the modified Becke–Johnson potential was employed. The modified Becke–Johnson potential was specifically chosen for its capability to improve the description of band gaps, particularly for systems with small band gaps, such as the LuXNi2Sn2 (X = V, Nb, and Ta) double-half Heusler materials examined in this study. This potential offers a more accurate representation of the electronic properties, enabling a more reliable analysis of the optical and thermoelectric characteristics of the materials under investigation. The examined LuXNi2Sn2 (X = V, Nb, and Ta) materials exhibit semiconductor behaviour, with band gaps smaller than 0.4 eV that can be controlled by varying the "X" atom. The charge carriers, specifically holes and electrons, exhibit light effective masses, indicating high mobility. Furthermore, these compounds exhibit low thermal expansion coefficients and satisfy the criteria for thermodynamic stability. In terms of optical properties, they display substantial absorption coefficients in the ultraviolet (UV) light region, high optical conductivity, and high reflectivity in the visible light region. Considering their favourable power factor and figure of merit characteristics, the LuXNi2Sn2 (X = V, Nb, and Ta) materials possess the potential to be promising candidates for thermoelectric applications. [ABSTRACT FROM AUTHOR]

The growth of epitaxial thin films from the Ruddlesden–Popper series of strontium iridates by magnetron sputtering is analyzed. It was found that, even using a non-stoichiometric target, the films formed under various conditions were consistently of the perovskite-like n = ∞ SrIrO3 phase, with no evidence of other RP series phases. A detailed inspection of the temperature–oxygen phase diagram underscored that kinetics mechanisms prevail over thermodynamics considerations. The analysis of the angular distribution of sputtered iridium and strontium species indicated clearly different spatial distribution patterns. Additionally, significant backsputtering was detected at elevated temperatures. Thus, it is assumed that the interplay between these two kinetic phenomena is at the origin of the preferential nucleation of the SrIrO3 phase. In addition, strategies for controlling cation stoichiometry off-axis have also been explored. Finally, the long-term stability of the films has been demonstrated. [ABSTRACT FROM AUTHOR]

Recently, the vectorial nonlinear optical processes driven by spin‐orbit coupling (SOC) light have come to the fore, leading to striking optical phenomena and important applications both in classical and quantum optics. However, research on the SOC‐mediated light‐atom interactions is still in its infancy. Here, the generation and manipulation of SOC mode through a vectorial four‐wave mixing (FWM) process in 85Rb vapor is demonstrated. Under the excitation of two SOC pump beams, multiple FWM paths can be simultaneously established due to the rich atomic Zeeman sublevels coupling with different circularly polarized components of SOC fields. A higher‐order cylindrical or more general SOC FWM signal is observed in the vectorial FWM process, which obeys angular momentum conservation and Gouy phase matching. In particular, quantum interference between different FWM paths plays a crucial role in manipulating the SOC mode of the generated FWM signal, revealing that the conversion of SOC mode is intrinsically quantum. This work provides a pathway toward deeper insight into the vectorial nonlinear optical processes and may advance technology for shaping spatially structured light, which is essential in applications such as nonlinear polarization imaging and the optical communication realm. [ABSTRACT FROM AUTHOR]

This article presents a concise survey of basic discrete and semi-discrete nonlinear models, which produce two- and three-dimensional (2D and 3D) solitons, and a summary of the main theoretical and experimental results obtained for such solitons. The models are based on the discrete nonlinear Schrödinger (DNLS) equations and their generalizations, such as a system of discrete Gross–Pitaevskii (GP) equations with the Lee–Huang–Yang corrections, the 2D Salerno model (SM), DNLS equations with long-range dipole–dipole and quadrupole–quadrupole interactions, a system of coupled discrete equations for the second-harmonic generation with the quadratic ( χ (2) ) nonlinearity, a 2D DNLS equation with a superlattice modulation opening mini-gaps, a discretized NLS equation with rotation, a DNLS coupler and its PT -symmetric version, a system of DNLS equations for the spin–orbit-coupled (SOC) binary Bose–Einstein condensate, and others. The article presents a review of the basic species of multidimensional discrete modes, including fundamental (zero-vorticity) and vortex solitons, their bound states, gap solitons populating mini-gaps, symmetric and asymmetric solitons in the conservative and PT -symmetric couplers, cuspons in the 2D SM, discrete SOC solitons of the semi-vortex and mixed-mode types, 3D discrete skyrmions, and some others. [ABSTRACT FROM AUTHOR]

The study of atomic spectroscopy has a profound relationship with quantum mechanics and its comprehension. Since Bohr’s success with a theory for the atom, it has been established that spectrum lines originate from transitions between different states. Moreover, the analysis of complex spectra reveals that there are groups of spectral lines that compose what is called a multiplet. To rationalize the multiplet structure, we need models to characterize and label the quantum states. The characterization of the atomic states is a common subject in classes of physical chemistry and inorganic chemistry, and there are basically two approaches to infer and label the energy states: (i) the LS coupling scheme and (ii) the jj coupling scheme. Usually, only the LS coupling is presented, and this ends up omitting its underlying assumptions. Here, we present a survey of both approaches, highlighting their premises and their adequacy towards different groups of the periodic table, ions, and excited states configurations. We show that by using benchmark data together with the Landé interval rule, the appropriate use of the jj coupling to understand the atomic spectra of heavier atoms is easily conveyed.

Spin angular momentum (SAM) and Orbital angular momentum (OAM) are two distinct forms of electromagnetic angular momentum (AM). Generally, circularly-polarized (CP) wave is deemed as the typical form of spin wave, which carries SAM only. In this work, the OAM characteristic of spin wave is found after stating the CP wave into the cylindrical coordinate: the spin wave contains two components along r and ϕ directions, which carry both SAM and OAM. Based on the OAM character of spin wave, an electromagnetic waveform with SAM in the center and SAM-OAM beside is demonstrated. In addition, since spin wave carries OAM naturally, a spin–orbit coupling mechanism is performed, which demands no spin Pancharatnam–Berry phase nor any phase modulation structure. All the results have been experimentally verified. Our research can be utilized in the theoretical studies of rotational electromagnetic and may be potentially applied in metamaterial, information and quantum research areas.

Two-dimensional multiferroic van der Waals (vdW) heterostructures are promising for nanoscale and multifunctional spintronic devices. Controllable perpendicular magnetic anisotropy in vdW heterostructure often plays a central role in stabilizing ferromagnetic order and lowering energy consumption. Here, we carry out first-principles calculations for CrI3/In2Se3 vdW heterostructure and investigate how its magnetic anisotropy is interrelated to the electronic structure. We show that the semiconducting nature of CrI3 is preserved but band gap decreases in monolayer-CrI3/In2Se3 and bilayer-CrI3/In2Se3 vdW heterostructures. The magnetoelectric effect of CrI3/In2Se3 vdW heterostructure enhances the magnetic moment of CrI3, but decreases the perpendicular magnetic anisotropy of CrI3. I-p orbital coupling matrix element is noteworthy in regard to the modulation of magnetic anisotropy. The MAE contribution of Cr atom slightly enhances but is still negligible by the reason of countervailing contribution of d-orbital coupling matrix elements. By reversing the ferroelectric polarization of In2Se3, the easy magnetization axis of monolayer CrI3 can be switched. These results will help to understand the magnetic anisotropy of multiferroic vdW heterostructure and may enable the development of nonvolatile memory devices.

Periodic spin-orbit motion is ubiquitous in nature, observed from electrons orbiting nuclei to spinning planets orbiting the Sun. Achieving autonomous periodic orbiting motions, along circular and noncircular paths, in soft mobile robotics is crucial for adaptive and intelligent exploration of unknown environments--a grand challenge yet to be accomplished. Here, we report leveraging a closed-loop twisted ring topology with a defect for an autonomous soft robot capable of achieving periodic spin-orbiting motions with programmed circular and re-programmed irregular-shaped trajectories. Constructed by bonding a twisted liquid crystal elastomer ribbon into a closed-loop ring topology, the robot exhibits three coupled periodic self-motions in response to constant temperature or constant light sources: inside-out flipping, self-spinning around the ring center, and self-orbiting around a point outside the ring. The coupled spinning and orbiting motions share the same direction and period. The spinning or orbiting direction depends on the twisting chirality, while the orbital radius and period are determined by the twisted ring geometry and thermal actuation. The flip-spin and orbiting motions arise from the twisted ring topology and a bonding site defect that breaks the force symmetry, respectively. By utilizing the twisting-encoded autonomous flip-spin-orbit motions, we showcase the robot's potential for intelligently mapping the geometric boundaries of unknown confined spaces, including convex shapes like circles, squares, triangles, and pentagons and concaves shapes with multi-robots, as well as health monitoring of unknown confined spaces with boundary damages. [ABSTRACT FROM AUTHOR]

The Magnetoelectric Spin‐Orbit (MESO) technology aims to bring logic into memory by combining a ferromagnet with a magnetoelectric (ME) element for information writing, and a spin‐orbit (SO) element for information read‐out through spin‐charge conversion. Among candidate SO materials to achieve a large MESO output signal, oxide Rashba two‐dimensional electron gases (2DEGs) have shown very large spin‐charge conversion efficiencies, albeit mostly in spin‐pumping experiments. Here, all‐electrical spin‐injection and spin‐charge conversion experiments in nanoscale devices harnessing the inverse Edelstein effect of SrTiO3 2DEGs are reported. Nanodevices aredesigned, patterned, and fabricated in which a spin current injected from a cobalt layer into the 2DEG is converted into a charge current. The spin‐charge conversion signal is optimized by applying back‐gate voltages and studied its temperature evolution. It further disentangles the inverse Edelstein contribution from spurious effects such as the planar Hall effect, the anomalous Hall effect, or the anisotropic magnetoresistance. The combination of non‐volatility and high energy efficiency of these devices can potentially lead to new technology paradigms for beyond‐CMOS computing architectures. [ABSTRACT FROM AUTHOR]

Layered honeycomb magnets with strong atomic spin–orbit coupling at transition metal sites have been intensively studied for the search of Kitaev magnetism and the resulting non-Abelian braiding statistics. α -RuCl 3 has been the most promising candidate, and there have been several reports on the realization of sibling compounds α -RuBr 3 and α -RuI 3 with the same crystal structure. Here, we investigate correlated electronic structures of α -RuCl 3 and α -RuI 3 by employing first-principles dynamical mean-field theory. Our result provides a valuable insight into the discrepancy between experimental and theoretical reports on transport properties of α -RuI 3 , and suggests a potential realization of correlated flat bands with strong spin–orbit coupling and a quantum spin-Hall insulating phase in α -RuI 3 . [ABSTRACT FROM AUTHOR]

The theoretical study [Phys. Rev. A, 2006, 74: 052338] shows that electron spin on liquid helium surface has a coherence time of up to 100 seconds, and thus could be used for implementing quantum information processing. However, this theory has not been experimentally verified, yet. The spin-orbit coupling of electrons on liquid helium may provide an alternative method for electron spin detection. Theoretically, the electronic spin-orbit coupling generated by microelectrode currents under the liquid helium membrane, together with the electric dipole transitions driven by microwaves, shall result in a spin-dependent height of electrons above liquid helium surface. This orbital motion is experimentally detectable by using the image-charge method [Phys. Rev. Lett.,2019,123: 086801]. A density matrix equation with electron spin-orbit coupling is established, and the vibrational motion of the image charge is numerically solved. The results show that different spin states will induce different image-currents. This difference provides an alternative method for electron spin detection. [ABSTRACT FROM AUTHOR]

We extend the Berezinskii diagrammatic technique to one-dimensional disordered spin systems, in which time-reversal invariance is broken due to a spin–orbit coupling term inducing left–right asymmetric scattering. We then use this formalism to theoretically describe the dynamics of the quantum boomerang effect, a recently discovered manifestation of Anderson localization. The theoretical results are confirmed by exact numerical simulations of wave-packet dynamics in a random potential. [ABSTRACT FROM AUTHOR]

In recent years, understanding the mechanism of thermally activated delayed fluorescence (TADF) has become the primary choice for designing high‐efficiency, low‐cost, metal‐free organic light emitting diodes (OLEDs). Herein, we propose a strategically designed chalcone based donor‐acceptor system, where intensification of delayed fluorescence with decrease in temperature (300 K to 100 K) is observed; the theoretical investigations of electronic states and orbital characters uncovered a new cold rISC pathway in donor‐acceptor system, where rISC occurs through the down‐conversation of higher triplet exciton (from T3) to lowest singlet state (S1), having negative energy splitting, thus no thermal energy is required. The comprehensive research described herein might open‐up new avenues in donor‐acceptor system over the conventional up‐convention of triplet exciton and demonstrates that not necessarily all delayed fluorescence are thermally activated (TADF). [ABSTRACT FROM AUTHOR]

We investigate the steady-state multi-stability in a cavity system containing spin–orbit coupled Bose–Einstein condensate and driven by a strong pump laser. The applied magnetic field splits the Bose–Einstein condensate into pseudo-spin states, which then become momentum sensitive with two counter propagating Raman lasers directly interacting with ultra-cold atoms. After governing the steady-state dynamics for all associated subsystems, we show the emergence of multi-stable behavior of cavity photon number, which is unlike previous investigation on cavity-atom systems. However, this multi-stability can be tuned with associated system parameters. Furthermore, we illustrate the occurrence of mixed-stability behavior for atomic population of the pseudo-spin- ↑ and spin- ↓ states, which appear in so-called bi-unstable form. The collective behavior of these atomic number states interestingly possesses a population transitional phase (or population equilibrium intersection) among both of the spin states, which can be enhanced and controlled by spin–orbit coupling and Zeeman field effects. Additionally, we illustrate the emergence of another equilibrium intersection mediated by the increase in mechanical dissipation rate of the pseudo-spin states. These equilibrium intersections or population transitional phase could be caused by the non-trivial behavior of synthetic spin state mediated by cavity. Our findings are not only crucial for the subject of optical switching but also could provide a foundation for future studies on mechanical aspect of synthetic atomic states with cavity quantum electrodynamics. [ABSTRACT FROM AUTHOR]

The promotion of intersystem crossing (ISC) is critical for achieving a high‐efficiency long‐persistent luminescence (LPL) from organic materials. However, the use of a transition‐metal complex for LPL materials has not been explored because it can also shorten the emission lifetime by accelerating the phosphorescence decay. Here, we report a new class of LPL materials by doping a monovalent Au‐carbene complex into a boron‐embedded molecular host. The donor‐acceptor systems exhibit photoluminescence with both high efficiencies (>57 %) and long lifetimes (ca. 40 ms) at room temperature. It is revealed that the Au atom promotes the population of low‐lying triplet excited states of the host aggregate (T1*) which can be converted into the charge‐transfer (CT) state, thereby resulting in afterglow luminescence. Moreover, the use of a chirality unit on the guest molecule results in the LPL being circularly polarized. This work illustrates that transition‐metal complexes can be used for developing organic afterglow systems by exquisite control over the excited state mechanism. [ABSTRACT FROM AUTHOR]

Recently, a variety of mechanisms have been discovered that extend the range of optical techniques for identifying and characterizing molecular chirality, beyond those associated with optical polarization. It is now evident that beams of light with a twisted wavefront, known as optical vortices, can also interact with chiral matter with a specificity determined by relative handedness. Exploring this chiral sensitivity of vortex light in its interactions with matter requires careful consideration of the symmetry properties that engage in such processes. Most of the familiar measures of chirality are directly applicable to either matter, or to light itself—but only to one or the other. To elicit the principles that determine the viability of distinctly optical vortex‐based forms of chiral discrimination invites a more universal approach to symmetry analysis, as is afforded by the common, fundamental physics of CPT symmetry. Taking this approach supports a comprehensive and straightforward analysis to identify the mechanistic origins of vortex chiroptical interactions. Careful inspection of selection rules for absorption also elicits the principles governing any identifiable engagement with vortex structures, providing a reliable basis to ascertain the viability of other forms of enantioselective vortex interaction. [ABSTRACT FROM AUTHOR]

We investigate the vortex lattice configuration in a rotating spin orbit-coupled spin-2 Bose–Einstein condensate confined in a quasi-two-dimensional harmonic trap. By considering the interplay between rotation frequency, spin–orbit couplings, and interatomic interactions, we explore a variety of vortex lattice structures emerging as a ground state solution. Our study focuses on the combined effects of spin–orbit coupling and rotation, analyzed by using the variational method for the single-particle Hamiltonian. We observe that the interplay between rotation and Rashba spin–orbit coupling gives rise to different effective potentials for the bosons. Specifically, at higher rotation frequencies, isotropic spin–orbit coupling leads to an effective toroidal potential, while fully anisotropic spin–orbit coupling results in a symmetric double-well potential. To obtain these findings, we solve the five coupled Gross–Pitaevskii equations for the spin-2 BEC with spin–orbit coupling under rotation. Notably, we find that the antiferromagnetic, cyclic, and ferromagnetic phases exhibit similar behavior at higher rotation. [ABSTRACT FROM AUTHOR]

We model Bi2Sr2CaCu2O8+δ(Bi2212) bilayer system by an inversion symmetry broken and time reversal non-invariant Bloch Hamiltonian involving interlayer tunnelling and spin–orbit coupling. The pseudo-gap (PG) phase of the bilayer is assumed to be chiral d-density wave ordered. We have found that the spin–orbit coupling (SOC) is inimical to this order. The presence of SOC was reported earlier in the PG phase in a spin- and angle-resolved photoemission spectroscopic measurement. We also report the theoretical study of the spin-momentum locking, due to the presence of a strong SOC. The non-trivial spin texture in k-space is found tuneable by electric field (and also by intercalation). [ABSTRACT FROM AUTHOR]

Numerical studies on the effect of surface relaxation, namely, the equilibrium change in the interplanar distance, exerted on the values of the magnetic and energy characteristics of a Fe/Pt/Fe system have been performed. The contribution of spin-orbit coupling to the value of magnetic anisotropy energy is studied as a function of ferromagnetic film thickness. [ABSTRACT FROM AUTHOR]

The influence of spin–orbit coupling (SOC) on ultrafast demagnetization dynamics is still an obscure issue. Ferromagnetic ternary alloy film containing Platinum element has the advantage that SOC strength can be regulated flexibly by varying the component ratio, thus is an excellent platform for investigating the dynamical effect of SOC. Here the fluence and component dependences of ultrafast demagnetization dynamics in ternary alloy L10-Fe0.5(Pd1-xPtx)0.5 films are studied by using time-resolved magneto-optical Kerr spectroscopy. An excitation-fluence dependent transition of demagnetization dynamics shows the Elliott-Yafet (EY) spin-flip scattering as the dominant mechanism of ultrafast demagnetization. We analyze the dynamics by a compatible fitting model and extract multiple characteristic time constants. It is clearly demonstrated that the gradual enhancement of SOC in fact decreases the spin-flip scattering and slow down the demagnetization process. We further show that the demagnetization time τm scales with the SOC strength ξ approximately under a dependence of τm∝ξ1/3, while a linear dependence exists between the spin–lattice relaxation time τs-l and ξ-6. These findings clarify the role of SOC in EY-dominated demagnetization dynamics and demonstrate an approach for tuning the speeds and duration of ultrafast demagnetization by regulating SOC strength.

This article is written on behalf of many colleagues, collaborators, and researchers in the field of complex oxides as well as current and former students and postdocs who continue to enable and undertake cutting-edge research in the field of multiferroics, magnetoelectrics, and the pursuit of electric-field control of magnetism. What I present is something that is extremely exciting from both a fundamental science and applications perspective and has the potential to revolutionize our world, particularly from a sustainability perspective. To realize this potential will require numerous new innovations, both in the fundamental science arena as well as translating these scientific discoveries into real applications. Thus, this article will attempt to bridge the gap between fundamental materials physics and the actual manifestations of the physical concepts into real-life applications. I hope this article will help spur more translational research within the broad materials community.

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.

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.

In this article, the modulation instability (MI) of open Bose–Bose mixtures with helicoidal spin–orbit coupling (SOC) was studied. Unlike previous spin–orbit (SO)-coupled Bose–Einstein condensate system with helicoidal gauge potential, the purpose of this article to study the input of the helicoidal SOC in the emergence of MI in open Bose–Bose mixtures by taking into account the Lee–Huang–Yang corrections to the coupled Gross–Pitaevskii equations. We present the detailed analyses of system parameters on the characteristics of MI and analytically conclude the parameter conditions for MI occurrence. Our results provide a potential way to manipulate the MI in the helicoidal SO-coupled open Bose–Bose mixtures.

ABSTRACTGaN-based semiconductors are deemed to be a potential candidate for developing spintronic devices owing to the artificially controllable spin-orbit coupling and the high Curie temperature of GaN-based diluted magnetic semiconductors. Spin injection, spin relaxation dynamics, and spin manipulation are the key issues in the development of GaN-based spintronic devices, which have been reviewed in this article. In the end, a brief section presents the research progress of GaN-based spintronic devices.

The transition from trivial to non-trivial phase in two-dimensional materials are called a topological phase transition (TPT). The Berry phase, non-local string order parameter, and edge states define the topological nature of the system. A newly discovered jacutingaite ma- terial Pt2HgSe3 is a layered material which occurs naturally in the form of minerals. The material can be exfoliated and was predicted as a quantum spin Hall insulator. Here, on the basis of density functional theory and tight-binding calculations, we explore Pt2Hg1−xTlxSe3 (x = 0.25, 0.50, 0.75, 1) to understand the electronic and topological properties. We start with the parent material Pt2HgSe3 wherein Hg is replaced partially with x amount of Tl, to tune the topological phases. From the electronic structure calculations, Pt2HgSe3 is found to be a non-trivial semimetal in it’s bulk. Upon electron doping, the material transforms to strong topological metallic phase. The topological Z2 invariant calculation shows TPT in Pt2Hg1−xTlxSe3 with weak topological insulating state (0;001) for x=0, to strong topological metal (1;000) for x=1, respectively.

Developing radical‐induced afterglow emission under ambient conditions is challenging since newly formed radical species are susceptible to air and water. In this work, long afterglow materials (up to 4 s) are realized by doping a series of N,N'‐diaryl‐5,10‐dihydrophenazine (DPP)derivatives into rigid cycloaliphatic epoxy resins (CER). The afterglow is found to result from the interaction between the matrix and the excited states of the dopants through the generation of radical species under continuous UV excitation, which can be regulated by the peripheral functional groups of the N‐phenyl substituents. Density functional theory (DFT) calculations predict that the introduction of electron‐withdrawing groups hinders the afterglow emission, which may be related to the reducing reduction potential and inefficient spin‐orbit coupling (SOC) coefficients. The afterglow emission of the radical‐based systems demonstrates a bright opportunity for information encryption, anti‐counterfeiting, and photolithography. [ABSTRACT FROM AUTHOR]

Three Eu3+ complexes containing a neutral tripodal ligand possessing a predictable coordination mode have been obtained and studied. The trispyrazolylmethane complexes have an aqua ligand in the coordination sphere, forming both the mononuclear species [Eu(HCPz3)H2O(NO3)3] and the dimer [Eu(HCPz3)H2O(CF3SO3)3]2, having a Chinese lantern structure, whereas the use of the methylated tripod leads to the water-free complex, [Eu(HC(PzMe2)3)(NO3)3]. A qualitative analysis of the magnetic susceptibility of polycrystalline samples demonstrated that the magnetic properties can be described using a simple Van Vleck formula with spin–orbit coupling parameter (λ = 383 ÷ 406 cm−1) close to the values for free Eu3+ ions. The stereochemical analysis of the coordination environment of [Ln(HC(PzMe2)3)(NO3)3] has shown that these complexes can be used as diamagnetic model systems to obtain information on the crystal field effects in the paramagnetic monoradical complexes, [LnRad(NO3)3], since both types of compounds have the same type of coordination polyhedron (symmetry point group D3h) and very close Ln–donor atom distances. [ABSTRACT FROM AUTHOR]

The band structures of two series of chiral single-walled gold nanotubes (5, n2) and (10, n2) have been calculated using the cylindrical wave method with inclusion of spin–orbit coupling. Compounds with high spin polarizability of the electronic structure and spin selectivity of conductivity have been revealed. They can be used as materials for design of molecular spintronics elements. [ABSTRACT FROM AUTHOR]

We investigate the itinerant ferromagnetism in a dipolar Fermi atomic system with the anisotropic spin–orbit coupling (SOC), which is traditionally explored with isotropic contact interaction. We first study the ferromagnetism transition boundaries and the properties of the ground states through the density and spin-flip distribution in momentum space, and we find that both the anisotropy and the magnitude of the SOC play an important role in this process. We propose a helpful scheme and a quantum control method which can be applied to conquering the difficulties of previous experimental observation of itinerant ferromagnetism. Our further study reveals that exotic Fermi surfaces and an abnormal phase region can exist in this system by controlling the anisotropy of SOC, which can provide constructive suggestions for the research and the application of a dipolar Fermi gas. Furthermore, we also calculate the ferromagnetism transition temperature and novel distributions in momentum space at finite temperature beyond the ground states from the perspective of experiment. [ABSTRACT FROM AUTHOR]

Unexpected, yet useful functionalities emerge when two or more materials merge coherently. Artificial oxide superlattices realize atomic and crystal structures that are not available in nature, thus providing controllable correlated quantum phenomena. This review focuses on 4d and 5d perovskite oxide superlattices, in which the spin–orbit coupling plays a significant role compared with conventional 3d oxide superlattices. Modulations in crystal structures with octahedral distortion, phonon engineering, electronic structures, spin orderings, and dimensionality control are discussed for 4d oxide superlattices. Atomic and magnetic structures, Jeff = 1/2 pseudospin and charge fluctuations, and the integration of topology and correlation are discussed for 5d oxide superlattices. This review provides insights into how correlated quantum phenomena arise from the deliberate design of superlattice structures that give birth to novel functionalities. [ABSTRACT FROM AUTHOR]

The utilization of triplet excitons is of great importance for organic light‐emitting diodes (OLEDs). Triplet–triplet annihilation (TTA) is one of the effective tactics to achieve high efficiency deep‐blue organic electroluminescence emitters by converting two triplet excitons into one singlet exciton. Whereas, in addition to the 25% electrogenerated singlet excitons, the proportion of radiative singlet excitons (RSE) produced by the TTA process is usually only 15%; thus the total radiative excitons are 40%. In this study, ≈35% of RSE is achieved by the TTA process (total 60%) with two deep‐blue emitters based on the isomeric naphthoimidazole (NI) unit and anthracene bridge. As a result, non‐doped OLEDs based on the two NI derivatives as emitting layers achieve maximum external quantum efficiencies of 10.9% and 11.2% with an identical deep‐blue emission peak of 452 nm, which are the best TTA OLEDs with a Commission Internationale de l'Eclairage chromaticity Y coordinate below 0.15. Theoretical and experimental results demonstrate that the TTA process can be improved owing to the efficient spin–orbit interactions, even though the energy levels of the triplet pairs are higher than the calculated second triplet excited states. [ABSTRACT FROM AUTHOR]

Improving the magneto-optical saturation signal of materials is a crucial area of research in the field of magneto-optical effect. Au@Pt nanohybrids (Au@Pt NHs) with surface plasmon resonance and spin–orbit coupling effects were fabricated using a microfluidic technique in this investigation. The Au@Pt NHs were directly dripped onto the CoFeB/W film as a deposition layer, and its dual-mode resonance was applied to increase the longitudinal saturated magneto-optical Kerr angle of the CoFeB/W film by 4.4 times. The innovative concept of using a dual-mode resonance in this paper provides a new idea for the further search of materials that have large magneto-optical coefficients. [ABSTRACT FROM AUTHOR]

Electronic nematicity has been found in a wide range of strongly correlated electron materials, resulting in the electronic states having a symmetry that is lower than that of the crystal that hosts them. One of the most astonishing examples is Sr3Ru2O7, in which a small in-plane component of a magnetic field induces significant resistivity anisotropy. The direction of this anisotropy follows the direction of the in-plane field. The microscopic origin of this field-induced nematicity has been a long-standing puzzle, with recent experiments suggesting a field-induced spin density wave driving the anisotropy. Here, we report spectroscopic imaging of a field-controlled anisotropy of the electronic structure at the surface of Sr3Ru2O7.We track the electronic structure as a function of the direction of the field, revealing a continuous change with the angle. This continuous evolution suggests a mechanism based on spin–orbit coupling resulting in compass-like control of the electronic bands. The anisotropy of the electronic structure persists to temperatures about an order of magnitude higher compared to the bulk, demonstrating novel routes to stabilize such phases over a wider temperature range [ABSTRACT FROM AUTHOR]

Electronic nematicity has been found in a wide range of strongly correlated electron materials, resulting in the electronic states having a symmetry that is lower than that of the crystal that hosts them. One of the most astonishing examples is Sr3Ru2O7, in which a small in-plane component of a magnetic field induces significant resistivity anisotropy. The direction of this anisotropy follows the direction of the in-plane field. The microscopic origin of this field-induced nematicity has been a long-standing puzzle, with recent experiments suggesting a field-induced spin density wave driving the anisotropy. Here, we report spectroscopic imaging of a field-controlled anisotropy of the electronic structure at the surface of Sr3Ru2O7.We track the electronic structure as a function of the direction of the field, revealing a continuous change with the angle. This continuous evolution suggests a mechanism based on spin–orbit coupling resulting in compass-like control of the electronic bands. The anisotropy of the electronic structure persists to temperatures about an order of magnitude higher compared to the bulk, demonstrating novel routes to stabilize such phases over a wider temperature range [ABSTRACT FROM AUTHOR]

We demonstrate that the XMR material ytterbium monoarsenide (YbAs) shows transitions from a trivial to a non-trivial topological phase with hydrostatic pressure of 20 GPa and maintains its topological character up to structural phase transition pressure. We observed band inversions close to the Fermi level at the X high symmetry point at 20 GPa and band parities are used to confirm the same with consideration of Spin-orbit coupling (SOC) effect. The evolution of the surface states and the bulk band structure in YbAs are discussed. [ABSTRACT FROM AUTHOR]