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The investigation of spin and polarization effects in ultra-high intensity laser–plasma and laser–beam interactions has become an emergent topic in high-field science recently. In this paper, we derive a relativistic kinetic description of spin-polarized plasmas, where quantum-electrodynamics effects are taken into account via Boltzmann-type collision operators under the local constant field approximation. The emergence of anomalous precession is derived from one-loop self-energy contributions in a strong background field. We are interested, in particular, in the interplay between radiation reaction effects and the spin polarization of the radiating particles. For this, we derive equations for spin-polarized quantum radiation reaction from moments of the spin-polarized kinetic equations. By comparing with the classical theory, we identify and discuss the spin-dependent radiation reaction terms and radiative contributions to spin dynamics. [ABSTRACT FROM AUTHOR]

The role of spin–orbit interaction has been recently reconsidered in high- T c cuprates, stimulated by the recent experimental observations of spin-polarized electronic states. However, due to the complexity of the spin texture reported, the origin of the spin polarization in high- T c cuprates remains unclear. Here, we present the spin- and angle-resolved photoemission spectroscopy (ARPES) data on the facing momentum points that are symmetric with respect to the Γ point, to ensure the intrinsic spin nature related to the initial state. We consistently found the very weak spin polarization only along the nodal direction, with no indication of spin-splitting of the band. Our findings thus call for a revision of the simple application of the spin–orbit interaction, which has been treated within the standard framework of the Rashba interaction in high- T c cuprates. [ABSTRACT FROM AUTHOR]

The relativistic inverse spin Hall effect (ISHE) plays a pivotal role in terahertz (THz) emission in magnet/heavy metal bilayers. Here, THz emission from RuO2/Py bilayers is reported due to not only the relativistic ISHE but also the nonrelativistic inverse altermagnetic spin splitting effect (IASSE) in RuO2. For the (100)‐oriented RuO2/Py bilayers, the THz emission is greatly enhanced owing to IASSE once the polarization direction of the spin current (from the Py layer induced by pump laser) is parallel to the Néel vector of RuO2, producing the anisotropic THz emission with twofold symmetry. In contrast, the RuO2(110)/Py bilayer only exhibits isotropic THz emission because of the absence of IASSE‐induced spin‐charge conversion in the (110)‐oriented RuO2 films. Apart from the fundamental significance of exploring the IASSE‐induced spin‐to‐charge conversion, the finding also enriches the physical mechanism and modulation method of THz emission in spintronic systems. [ABSTRACT FROM AUTHOR]

Inspired by potential application prospects of spintronics and valleytronics, a novel heterobilayer Janus structure is designed by replacing the chalcogenide atomic layers in the original bilayer MoS2. Based on first-principles calculations, it is found that the SMoS/SeMoS structure exhibits a direct band-gap semiconductor and a typical type-II band alignment with longer carrier lifetime. The transition metal (TM) atom represented by V/Cr/Mn can be stably adsorbed on the heterobilayer Janus SMoS/SeMoS sheet and effectively introduce magnetic moments (m). The calculation results demonstrate that the most stable adsorption site of the TM atom is CX(A), and the TM (V/Cr/Mn) adatom modified SMoS/SeMoS system is converted into metal (V-) or half-metal (Cr/Mn-), respectively. Under the coupling of different indirect exchange interactions, the structure exhibits stable intrinsic anti-ferromagnetic interactions for V-SMoS/SeMoS and ferromagnetic ground state for Cr/Mn-SMoS/SeMoS, respectively, and the magnetic transition temperature (T c) reaches a high temperature or even room temperature. Moreover, the robust out-of-plane magnetocrystalline anisotropy energy ensures stable long-range magnetic order. Specifically, the combination of spin injection and strong spin–orbit coupling interaction effectively breaks the time-reversal symmetry, which leads to valley polarization of the system. Based on this, the biaxial strain can effectively regulate the electronic structure, magnetic properties and valley polarization of TM-SMoS/SeMoS nanosheets with double breaking of spatial-inversion and time-reversal symmetry. [ABSTRACT FROM AUTHOR]

A possibility of generating a high degree of spin polarization of 13C and 15N nuclei in the cyanide ion, which forms the coordination bond with the metal ion, using parahydrogen is demonstrated for the first time for the new iridium carbene complex as an example. The spin–spin interaction constants in the synthesized complex and the structure of the hydride intermediate are determined by an analysis of the 13С NMR spectra detected using broadband and selective heteronuclear decoupling. The cyanide ion is shown to coordinate to the metal ion by the carbon atom in one of two equatorial positions, and two pyridine molecules are arranged in the axial and equatorial positions. The signal amplification factors for 13С and 15N nuclei of the cyanide anion (5665 and –49 555, respectively) are estimated by NMR spectroscopy of the polarized substrate using the SABRE method from an ultralow magnetic field of 0.5 μT. This amplification corresponds to 15.5% polarization of nitrogen nuclei achieved within several seconds at room temperature. [ABSTRACT FROM AUTHOR]

To meet the current requirements of diluted magnetic semiconductors (DMSs) resulting from continuous advancements in spintronics, designing d0 DMSs with high stability, spin polarization, and Curie temperature is essential. Present research on introducing d0 magnetism is limited to monatomic doping, lacking regulation measures for local magnetic moments and long range magnetic coupling. Herein, an adjacent doping strategy is employed to introduce degrees of freedom for tuning the magnetic properties of d0 DMSs. It is observed that by introducing Si and O atoms as central and adjacent dopants, respectively, the intrinsically nonmagnetic hexagonal boron nitride (h-BN) exhibits significant local magnetic moments. Furthermore, it is observed that the ionization energy, total magnetic moment, magnetic coupling, and Curie temperature of the doped h-BN are susceptible to the Si–O coordination. Subsequently, a magnetic half-metal (Si–O3-doped h-BN) with high thermal stability, 100% spin polarization, long range ferromagnetic coupling, and high Curie temperature is designed through high Si–O coordination doping. This study proposes a feasible approach for introducing tunable d0 magnetism using the design of Si–O adjacent-doped h-BN as an example. [ABSTRACT FROM AUTHOR]

2D magnetic van der Waals (vdW) junctions have attracted intensive attention due to their easily controllable thickness and clear interface compared to conventional magnetic multilayer films, which provide a perfect platform to control the performance of spintronic devices. Herein, based on the experimentally fabricated FeCl2 flaks with interlayer antiferromagnetism and intralayer ferromagnetism, we explore the spin transport properties of two classes of vdW junctions with an Au electrode, Au/FeCl2/Au (FeCl2 as the tunnel barrier) and Au/FeCl2/barrier/FeCl2/Au (MoS2 or graphene as the tunnel barrier), and focus on the effects of different barriers and the number of layers. It is found that from monolayer to bilayer FeCl2 in Au/FeCl2/Au, the spin filtering effect is considerably increased due to the weakened interface effect, and almost complete spin polarized current can be obtained. For Au/FeCl2/MoS2/FeCl2/Au, whether the number of layers of MoS2 or FeCl2 is increased from monolayer to bilayer, the tunnel magnetoresistance (TMR) becomes higher due to the high spin polarization of FeCl2, which can reach 1 374 000%. The high TMR of 763 000% can also be achieved for Au/FeCl2/graphene/FeCl2/Au. This work suggests potential applications for FeCl2 flaks in 2D vdW spin filters and spin valves and will stimulate broad studies on layer- and barrier-controllable vdW spintronic devices. All calculations are performed by using the first-principles combined with non-equilibrium Green's function method. [ABSTRACT FROM AUTHOR]

Standard relativistic hydrodynamics has been successful in describing the properties of the strongly interacting matter produced in the heavy-ion collision experiments. Recently, there has been a significant theoretical advancement in this field to explain spin polarization of hadrons emitted in these processes. Although current models have successfully explained some of the experimental data based on the coupling between spin polarization and vorticity of the medium, they still lack a clear understanding of the differential measurements. This is commonly interpreted as an indication that the spin needs to be treated as an independent degree of freedom whose dynamics is not entirely bound to flow circulation. In particular, if the spin is a macroscopic property of the system, in equilibrium its dynamics should follow hydrodynamic laws. Here, we develop a framework of relativistic hydrodynamics which includes spin degrees of freedom from the quantum kinetic theory for Dirac fermions and use it for modeling the dynamics of matter. Following experimental observations, we assume that the polarization effects are small and derive conservation laws for the net baryon current, the energy–momentum tensor and the spin tensor based on the de Groot–van Leeuwen–van Weert definitions of these currents. We present various properties of the spin polarization tensor and its components, analyze the propagation properties of the spin polarization components, and derive the spin-wave velocity for arbitrary statistics. We find that only the transverse spin components propagate, analogously to the electromagnetic waves. Finally, using our framework, we study the space–time evolution of the spin polarization for the systems respecting certain space–time symmetries and calculate the mean spin polarization per particle, which can be compared to the experimental data. We find that, for some observables, our spin polarization results agree qualitatively with the experimental findings and other model calculations. [ABSTRACT FROM AUTHOR]

Multi-directional spin-to-charge conversion—in which spin polarizations with different orientations can be converted into a charge current in the same direction—has been demonstrated in low-symmetry materials and interfaces. This is possible because, in these systems, spin-to-charge conversion can occur in unconventional configurations in which charge current, spin current, and polarization do not need to be mutually orthogonal. Here, we explore, in the low temperature regime, the spin-to-charge conversion in heterostructures of graphene with the low-symmetry 1T' phase of MoTe2. First, we observe the emergence of charge conversion for out-of-plane spins at temperatures below 100 K. This unconventional component is allowed by the symmetries of both MoTe2 and graphene and likely arises from spin Hall effect in the spin–orbit proximitized graphene. Moreover, we examine the low-temperature evolution of non-local voltage signals arising from the charge conversion of the two in-plane spin polarizations, which have been previously observed at higher temperature. As a result, we report omni-directional spin-to-charge conversion—for all spin polarization orientations—in graphene/MoTe2 heterostructures at low temperatures. [ABSTRACT FROM AUTHOR]

We propose a method of cooling nuclear spin systems of solid-state nanostructures by applying a time-dependent magnetic field synchronized with spin fluctuations. Optical spin noise spectroscopy is considered a method of fluctuation control. Depending on the mutual orientation of the oscillating magnetic field and the probe light beam, cooling might be either provided by dynamic spin polarization in an external static field or result from population transfer between spin levels without build-up of a net magnetic moment ("true cooling"). [ABSTRACT FROM AUTHOR]

The structural, electronic, magnetic, and optical properties of MFe2O4 (M = Ni, Fe, Co) ferrites were investigated by employing Cambridge Serial Total Energy Package code using density functional theory. LDA+U was used to investigate the structural, electronic, magnetic, and optical properties of MFe2O4 (M = Ni, Fe, Co) ferrites at different pressures 0, 5, 10, 15, and 20 GPa. The simulated X‐ray diffraction (XRD) pattern of MFe2O4 (M = Ni, Fe, Co) ferrites was investigated and the computed lattice parameters decreased 8.62–8.32, 8.68–8.35, and 8.567–8.267 Å at 0–20 GPa, respectively. XRD revealed that the unit cell's volumes (640.50–575.93, 653.97–582.182, 627.22–563.550), X‐ray densities (4.86–5.40, 4.70–5.28, 3.97–4.43), and interatomic distance (2.6099–2.5180, 2.6221–2.4260, 2.5831–2.4928) of MFe2O4 (M = Ni, Fe, Co) ferrites were also decreased with the increasing pressure 0–20 GPa, respectively. The LDA+U calculations predicted that the NiFe2O4, Fe3O4, and CoFe2O4 ferrite followed the properties of a semiconductor exhibiting a direct band gap of 1.2, 1.13, and 0.710 eV at 0 GPa which were decreased to 0.846, 0.710, and 0.461 eV at 20 GPa, respectively. The computed density of states revealed that MFe2O4 (M = Ni, Fe, Co) ferrites exhibited good spin polarization behavior, and Ni–O, Fe–O, and Co–O bonds were covalent. The Mullikens investigated the ted decrease in bong length of MFe2O4 (M = Ni, Fe, Co) ferrites versus 0–20 GPa as well as according to Hirschfeld analysis the magnetic moment (3.348–3.335, 4.12–4.10, 3.737–3.735) and saturation magnetization (79.06–78.7, 99.33–98.9, 88.93–88.352) of MFe2O4 (M = Ni, Fe, Co) ferrites were decreased with increased pressure 0–20 GPa, respectively. The reflectivity and absorption specialize in visible and ultraviolet regions showing their stability for optoelectronics, photocatalysis, and solar cell applications. [ABSTRACT FROM AUTHOR]

Chiral‐induced spin selectivity is recently demonstrated in a range of spin‐dependent optoelectronics and electrochemistry. Herein, a new type of amorphous chiral tartaric acid‐FeNi coordination polymer fabricated by electrodeposition methods, achieving both high spin‐polarization and high electrocatalytic activity for oxygen evolution, is reported. Circular dichroism shows signature optical activity from the coordination polymer. Conductive atomic force microscopy measurements demonstrate a high spin polarization through the chiral electrocatalyst, which significantly suppresses the formation of hydrogen peroxide byproducts compared to the achiral ones. These chiral Fe‐Ni electrocatalysts exhibit a low overpotential of 205 and 280 mV to achieve 10 and 100 mA cm−2, respectively. [ABSTRACT FROM AUTHOR]

We study the impact of the QCD critical point (CP) on the spin polarization of Λ -hyperon generated by the thermal vorticity in viscous quark gluon plasma (QGP). The equations of the relativistic causal viscous hydrodynamics have been solved numerically in (3+1) dimensions to evaluate the thermal vorticity. The effects of the CP have been incorporated through the equation of state (EoS) and the scaling behavior of the transport coefficients. We observe a significant suppression of the spin polarization around mid-rapidity region induced by the CP and propose that such changed behaviour of the spin polarization can be used to detect the CP. To the best of our knowledge this is the first study on the effects of critical point on the spin polarization in QCD matter. [ABSTRACT FROM AUTHOR]

A subclass of ternary intermetallic known as Heusler compounds is being employed in the steel industry to increase material strength. This study examines the structural, electrical, optical, and magnetic properties of Co2VZ (Z=Al, Bi, Ge, Si) compounds using two different methods. First is full potential linearized augmented plane wave (FP-LAPW) method by WIEN2k and second is pseudo potential method by Atomic Tool Kit-Virtual Nano-Lab. The equivalent energy gaps in the minority-spin of Co2VZ (Z= Al, Bi, Ga, Ge) with WIEN2k code, which displays 100% spin polarization, are 0.703, 0.384, 0.186, and 0.67 eV near to the Fermi level. Furthermore, it is discovered that these compounds are absolutely half-metallic ferromagnetic (HMF). With the exception of Co2VBi, which exhibits metallic properties, the aforementioned compounds exhibit 0.525, 0.0, 0.553, and 0.786 eV band gaps in the ATK-VNL code and indicate 100% spin polarization. The magnetic moments of the compounds Co2VZ (Z= Al, Bi, Ga, Ge) are found to be 2.976, 4.003, 1.989, and 3.001 µB, respectively, in the WIEN2k code. The relative magnetic moments of the aforementioned compounds are also 1.991, 3.947, 1.999, and 2.997 µB, according to the ATK-VNL code. [ABSTRACT FROM AUTHOR]

Both Ti2FeGe and CoTiFeGe compounds were designed based on density functional theory within GGA and mBJ-GGA approximations. Lattice parameter optimization in ferromagnetic and nonmagnetic phases for XA type structures were done in order to predict the magnetic stable ground state. The calculated total energy indicates that the most stable phase of XA type ordering is ferromagnetic state. The band structure and density of states for XA type ordering for the studied alloys exhibit half-metallic nature using GGA and mBJ-GGA approaches that is a precursor for high spin polarization in those alloys. Except for Ti2FeGe alloy, which exhibits metallic character when we used mBJ-GGA method. The calculated energy bands indicate that Ti2FeGe (CoTiFeGe) is an indirect band gap and the value of gap is 0.606 eV (0.490 eV) using GGA scheme and it is 0.00 eV (0.982 eV) by mBJ-GGA method. The elastic properties, such as stability, hardness, stiffness, ductility and brittleness were explored and determined by simulated elastic constants. The anisotropy of the stable compounds Ti2FeGe and CoTiFeGe have values in 3.79 and 2:73, respectively. Also, the Ti2FeGe and CoTiFeGe compounds follow the necessary Slater–Pauling rule conditions Mtot = NV-18 and Mtot = NV-24 for half-metallicity and they have a total magnetic moment of 2 µB and 1 µB, respectively. Their optical properties have confirmed semiconducting behavior and their main optical response occurs in the infrared (IR) and visible ranges and the very low loss in the same region, along with existence absorption, make them as suitable for optoelectronic applications for novel infrared (IR) detector devices. The substitution by Co led to a slight blue shift of the optical peaks. [ABSTRACT FROM AUTHOR]

The study of heterogeneous reactions for enantiomeric processes based on inorganic crystals has been resurgent in recent years. However, the question remains how homochirality develops in nature and chemical reactions. Here, the successful growth of B20 group PdGa single crystals with different chiral lattices enabled us to achieve enantioselective recognition of 3,4‐dihydroxyphenylalanine (DOPA) based on a new mechanism, namely orbital angular momentum (OAM) polarization. The orbital textures of PdGa crystals indicate large OAM polarization near the Fermi level and carrying opposite signs. A positive or negative magnetization in the [111] direction is expected depending on the chiral lattice of PdGa crystals. Due to this, the adsorption energies of PdGa crystals and DOPA molecules differ depending on how well the O‐2p orbital of DOPA pairs with the Pd‐4d orbital of PdGa. The results provide one possible explanation for how chirality arises in nature by providing an enantioselective route with pure inorganic crystals. [ABSTRACT FROM AUTHOR]

Herein, the spin‐polarized edge‐state transport properties in L‐shaped zigzag MoS2$\left(\text{MoS}\right)_{2}$ nanodevice (L-zMoS2ND$\left(\text{L�?zMoS}\right)_{2} \text{ND}$) are investigated based on tight‐binding model, Green's function method, and ballistic transport theory. The spin conductance and spin polarization are calculated by considering external exchange field and electric field. It is shown in the results that the spin conductance is closely related to the configuration of atomic non‐consistence on the edge of L-zMoS2ND$\left(\text{L�?zMoS}\right)_{2} \text{ND}$. Meanwhile, the spin conductance is determined by the spin channel opening on the edge, which can be modulated by external fields. The configuration characteristic and external fields give rise to effects of sublattice mismatch and spin mismatch on the edge channels, respectively. As a consequence, mismatch effects are actually employed to modulate the spin channel on the edge of L-zMoS2ND$\left(\text{L�?zMoS}\right)_{2} \text{ND}$, and 100% spin polarization is realized selectively. Moreover, the corresponding local density of states distributions are plotted to reveal the modulation of the spin‐resolved edge‐state and the spin‐filtering effects in the real space. These spin‐polarized edge‐state transport properties in L-zMoS2ND$\left(\text{L�?zMoS}\right)_{2} \text{ND}$ can have potential application in various kinds of spin valves and spin filters in nanocircuits. [ABSTRACT FROM AUTHOR]

Density functional theory in the framework of generalized gradient approximation (GGA) of Perdew–Burke–Ernzerhof to investigate the effects of some selected transition metal (TM) and rare‐earth metal (RE) dopants on the electronic and magnetic properties of a 2D molybdenum disulfide (MoS2) monolayer is reported. The results demonstrate that it is energetically stable to incorporate Ni and Cu in MoS2 structure under Mo‐rich conditions. The pristine MoS2 monolayer has a calculated direct bandgap of 1.70 eV and experiences significant reduction in the gap due to the defects. There is observed induced magnetic behavior due to the tight binding effect originating from the localized dopants and the nearest‐neighbor Mo atoms, with magnetic moments ranging between 0.82 and 3.00 μB. Some of the dopants result in 100%$$ spin polarization which is useful for engineering spin filter devices on magnetic MoS2 nanostructures. [ABSTRACT FROM AUTHOR]

The structural, elastic, electronic, and magnetic properties of the CrCoSi, MnCoSi parent half-Heusler (HH) alloys, and their CrMnCo2Si2 derivative double half-Heusler (DHH) compound are studied, utilizing the augmented plane wave method, which is based on density functional theory and implemented in the WIEN2k code. The stability of HH structure of the CrCoSi and MnCoSi alloys has been checked for their non-magnetic and ferromagnetic phases, leading to that the latter phase of the type I arrangement is the most stable. The CrMnCo2Si2 DHH alloy, derivative from the found structural and magnetic ground states of CrCoSi and MnCoSi HH alloys, is constructed and investigated. This DDH as well as its CrCoSi parent HH are found to be resistant to deformation and can be classified as ductile materials, whereas the MnCoSi compound is brittle. By the gradient generalized approximation (GGA), the electronic structures of CrCoSi, MnCoSi, and CrMnCo2Si2compounds exhibit a metallic behavior in the spin-up channel and a semiconducting behavior in the spin-dn channel, with band gaps (half-metallic gaps) of 0.851(0.020), 0.852(0.021), and 0.531(0.002) eV, respectively. The half-metallicity of CrMnCo2Si2 DHH is retained with smaller (larger) band gap (half-metallic gap) of 0.38(0.106) eV than that of GGA, using GGA + U approximation. In addition, the total magnetic moments are found to be 1, 2, and 3 µB for CrCoSi, MnCoSi, and CrMnCo2Si2, respectively. Therefore, these alloys can be good candidates for spinitronic applications due to their half-metallicity. [ABSTRACT FROM AUTHOR]

The study of heterogeneous reactions for enantiomeric processes based on inorganic crystals has been resurgent in recent years. However, the question remains how homochirality develops in nature and chemical reactions. Here, the successful growth of B20 group PdGa single crystals with different chiral lattices enabled us to achieve enantioselective recognition of 3,4‐dihydroxyphenylalanine (DOPA) based on a new mechanism, namely orbital angular momentum (OAM) polarization. The orbital textures of PdGa crystals indicate large OAM polarization near the Fermi level and carrying opposite signs. A positive or negative magnetization in the [111] direction is expected depending on the chiral lattice of PdGa crystals. Due to this, the adsorption energies of PdGa crystals and DOPA molecules differ depending on how well the O‐2p orbital of DOPA pairs with the Pd‐4d orbital of PdGa. The results provide one possible explanation for how chirality arises in nature by providing an enantioselective route with pure inorganic crystals. [ABSTRACT FROM AUTHOR]

Spin- and angle-resolved photoemission spectroscopy (SARPES) with high efficiency and resolution plays a crucial role in exploring the fine spin-resolved band structures of quantum materials. Here, we report the performance of the SARPES instrument with a second-generation home-made multichannel very-low-energy-electron-diffraction spin polarimeter. Its energy and angular resolutions achieve 7.2 meV and 0.52°, respectively. We present the results of SARPES measurements of Bi(111) film to demonstrate its performance. Combined with the density functional theory calculations, the spin polarization of the bulk states was confirmed by the spin-layer locking caused by the local inversion asymmetry. The surface states at a binding energy of 0.77 eV are found with 1.0 ± 0.11 spin polarization. Better resolutions and stability compared with the first-generation one provide a good platform to investigate the spin-polarized electronic states in materials. [ABSTRACT FROM AUTHOR]

Using the first-principles calculations based on density functional theory (DFT) within the generalized gradient approximation (GGA), Ti2RuAl full-Heusler compound is studied. The electronic structure, magnetic, and optical properties of Ti2-based full Heusler compound Ti2RuAl are calculated and analyzed using the Wien2k package. The CuHg2Ti-type structure is found to be more favorable than the AlCu2Mn-type structure for this compound. The Ti2RuAl Heusler compound exhibits a ferrimagnetic half-metallic behavior with the total magnetic moment of 1 µB at the equilibrium lattice constant 6.24 Å. The total magnetic moment of Ti2RuAl is in agreement with the Slater-Pauling rule mtot = ztot–18 and hence has integral magnetic moments which is due to 100% spin polarization at Fermi energy. Ti2RuAl has an energy gap in the spin-down channel of 0.229 eV. This compound keeps a 100% of spin polarization for lattice constant change in the range of 5.8–6.5 Å. The Curie temperature of Ti2RuAl is estimated to be 451 K using the mean field approximation (MFA). In addition, optical properties like dielectric function, reflectivity, energy loss function, absorption coefficient, and optical conductivity are calculated. [ABSTRACT FROM AUTHOR]

A systematic structure and property investigation of MnGen− (n = 3–14) was conducted by means of density functional theory coupled with mass-selected anion photoelectron spectroscopy. This combined theoretical and experimental study allows global minimum and coexistence structures to be identified. It is found that the pentagonal bipyramid shape is the basic framework for the nascent growth process of MnGen− (n = 3–10), and from n = 10, the endohedral structures can be found. For n = 12, the anion MnGe12− cluster probably includes two isomers: a major isomer with a puckered hexagonal prism geometry and a minor isomer with a distorted icosahedron geometry. Specifically, the puckered hexagonal prism isomer follows the Wade–Mingos rules and can be suggested as a new kind of superatom with the magnetic property. Furthermore, the results of adaptive natural density partitioning and deformation density analyses suggest a polar covalent interaction between Ge and Mn for endohedral clusters of MnGe12−. The spin density and natural population analysis indicate that MnGen− clusters have high magnetic moments localized on Mn. The density of states diagram visually shows the significant spin polarization for endohedral structures and reveals the weak interaction between the Ge 4p orbital and the 4s, 3d orbitals of Mn. [ABSTRACT FROM AUTHOR]

Several proposals are available to get selective spin transmission through different nano-junctions and in all the cases the regulation is done either by applying a magnetic field or by tuning spin–orbit (SO) coupling. In the present work, we explore a separate scheme where the spin-dependent transport is regulated externally by irradiating a quantum ring that bridges the contact electrodes. This is a new proposal of generating spin selective transmission through a nano-junction, to the best of our knowledge. A high degree of spin polarization along with its phase alteration can be achieved by suitably adjusting the irradiation, circumventing the regulation of magnetic field and/or SO coupling. The effect of irradiation is included through the well-known Floquet-Bloch ansatz, where all the spin-dependent transport phenomena are worked out using Green's function formalism following the Landauer–Büttiker prescription within a tight-binding framework. Precise dependencies of light irradiation, SO coupling, magnetic flux threaded by the ring, interface sensitivity, system temperature, and impurities on spin polarization are critically investigated. Our analysis may give a new platform for spin selective electron transmission and make it applicable to other complex nano-structured materials also. We strongly believe that the present proposal can be examined in a suitable laboratory. [ABSTRACT FROM AUTHOR]

Electronic structure methods emerging from the combination of multiconfigurational wave functions and density functional theory (DFT) aim to take advantage of the strengths of the two nearly antagonistic theories. One of the common strategies employed to merge wave function theory (WFT) with DFT relies on the range separation of the Coulomb operator in which DFT functionals take care of the short-distance part, while long-range inter-electronic interactions are evaluated by using the chosen wave function method (WFT–srDFT). In this work, we uncover the limitations of WFT–srDFT in the characterization of open-shell systems. We show that spin polarization effects have a major impact on the (short-range) DFT exchange energy and are of vital importance in order to provide a balanced description between closed and open-shell configurations. We introduce different strategies to account for spin polarization in the short range based on the definition of a spin polarized electron density and with the use of short-range exact exchange. We test the performance of these approaches in the dissociation of the hydrogen molecule, the calculation of energy gaps in spin-triplet atoms and molecular diradicals, and the characterization of low-lying states of the gallium dimer. Our results indicate that the use of short-range DFT correlation in combination with a (full-range) multiconfigurational wave function might be an excellent approach for the study of open-shell molecules and largely improves the performance of WFT and WFT–srDFT. [ABSTRACT FROM AUTHOR]

We report the implementation of a Fock-operator complete-active space self-consistent field (CAS-SCF) method combined with frozen-density embedding (FDE) into the KOALA quantum-chemistry program. The implementation is based on configuration interaction from an unrestricted reference determinant and is able to treat electronic configurations such as singlet, triplet, or quintet states embedded in a molecular environment. In order to account for possible spin polarization effects, the FDE contribution is extended to the unrestricted case. We assess the convergence obtained with the implementation at the example of a stretched lithium dimer with significant multi-reference character. The efficiency of the implementation enables the orbital optimization for 25 states in a state-average SA[S0–S10,T1–T12,Q1–Q2]-CAS(10,10)-SCF calculation for the retinal molecule using a def2-TZVP basis. The FDE ansatz leads to orbitals localized by definition on the target system, thus facilitating the orbital selection required for CAS methods in complex environments. [ABSTRACT FROM AUTHOR]

The mechanism of the magnetic compass sense of migratory songbirds is thought to involve magnetically sensitive chemical reactions of light-induced radical pairs in cryptochrome proteins located in the birds' eyes. However, it is not yet clear whether this mechanism would be sensitive enough to form the basis of a viable compass. In the present work, we report spin dynamics simulations of models of cryptochrome-based radical pairs to assess whether accumulation of nuclear spin polarization in multiple photocycles could lead to significant enhancements in the sensitivity with which the proteins respond to the direction of the geomagnetic field. Although buildup of nuclear polarization appears to offer sensitivity advantages in the more idealized model systems studied, we find that these enhancements do not carry over to conditions that more closely resemble the situation thought to exist in vivo. On the basis of these simulations, we conclude that buildup of nuclear polarization seems unlikely to be a source of significant improvements in the performance of cryptochrome-based radical pair magnetoreceptors. [ABSTRACT FROM AUTHOR]

The reaction kinetics of spin‐polarized oxygen evolution reaction (OER) can be enhanced by ferromagnetic (FM) catalysts under an external magnetic field. However, applying a magnetic field necessitates additional energy consumption and creates design difficulties for OER. Herein, we demonstrate that a single‐domain FM catalyst without external magnetic fields exhibits a similar OER increment to its magnetized multi‐domain one. The evidence is given by comparing the pH‐dependent increment of OER on multi‐ and single‐domain FM catalysts with or without a magnetic field. The intrinsic activity of a single‐domain catalyst is higher than that of a multi‐domain counterpart. The latter can be promoted to approach the former by the magnetization effect. Reducing the FM catalyst size into the single‐domain region, the spin‐polarized OER performance can be achieved without a magnetic field, illustrating an external magnetic field is not a requirement to reap the benefits of magnetic catalysts. [ABSTRACT FROM AUTHOR]

The reaction kinetics of spin‐polarized oxygen evolution reaction (OER) can be enhanced by ferromagnetic (FM) catalysts under an external magnetic field. However, applying a magnetic field necessitates additional energy consumption and creates design difficulties for OER. Herein, we demonstrate that a single‐domain FM catalyst without external magnetic fields exhibits a similar OER increment to its magnetized multi‐domain one. The evidence is given by comparing the pH‐dependent increment of OER on multi‐ and single‐domain FM catalysts with or without a magnetic field. The intrinsic activity of a single‐domain catalyst is higher than that of a multi‐domain counterpart. The latter can be promoted to approach the former by the magnetization effect. Reducing the FM catalyst size into the single‐domain region, the spin‐polarized OER performance can be achieved without a magnetic field, illustrating an external magnetic field is not a requirement to reap the benefits of magnetic catalysts. [ABSTRACT FROM AUTHOR]

Carbon-based single-atom catalysts (SACs) for electrochemical nitrogen reduction reaction (NRR) have received increasing attention due to their sustainable, efficient, and green advantages. However, at present, the research on carbon nanotubes (CNTs)-based NRR catalysts is very limited. In this paper, using FeN3@(n, 0) CNTs (n = 3 ~ 10) as the representative catalysts, we demonstrate that the CNT curvatures will affect the spin polarization of the catalytic active centers, the activation of the adsorbed N2 molecules and the Gibbs free energy barriers for the formation of the critical intermediates in the NRR processes, thus changing the catalytic performance of CNT-based catalysts. Zigzag (8, 0) CNT was taken as the optimal substrate, and twenty transition metal atoms (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Nb, Mo, Tc, Ru, Rh, Pd, W, Re, Ir, and Pt) were embedded into (8, 0) CNT via N3 group to construct the NRR catalysts. Their electrocatalytic performance for NRR were examined using DFT calculations, and TcN3@(8, 0) CNT was screened out as the best candidate with a low onset potential of − 0.53 V via the distal mechanism, which is superior to the molecules- or graphene-support Tc catalysts. Further electronic properties analysis shows that the high NRR performance of TcN3@(8, 0) CNT originates from the strong d-2π* interaction between the N2 molecule and Tc atom. TcN3@(8, 0) CNT also exhibits higher selectivity for NRR than the competing hydrogen evolution reaction (HER) process. The present work not only provides a promising catalyst for NRR, but also open up opportunities for further exploring of low-dimensional carbon-based high efficiency electrochemical NRR catalysts. [ABSTRACT FROM AUTHOR]

Graphene nanoribbons (GNRs) and nanographenes synthesized by on‐surface reactions using tailor‐made molecular precursors offer an ideal playground for a study of magnetism towards nano‐spintronics. Although the zigzag edge of GNRs has been known to host magnetism, the underlying metal substrates usually veil the edge‐induced Kondo effect. Here, we report the on‐surface synthesis of unprecedented, π‐extended 7‐armchair GNRs using 7‐bromo‐12‐(10‐bromoanthracen‐9‐yl)tetraphene as the precursor. Characterization by scanning tunneling microscopy/spectroscopy revealed unique rearrangement reactions leading to pentagon‐ or pentagon/heptagon‐incorporated, nonplanar zigzag termini, which demonstrated Kondo resonances even on bare Au(111). Density functional theory calculations indicate that the nonplanar structure significantly reduces the interaction between the zigzag terminus and the Au(111) surface, leading to a recovery of the spin localization of the zigzag edge. Such a distortion of planar GNR structures offers a degree of freedom to control the magnetism on metal substrates. [ABSTRACT FROM AUTHOR]

In the current stage, valley-contrasting physics is mainly rooted in nonmagnetic and/or ferromagnetic hexagonal lattices and is rarely used to observe the simultaneous spin and valley polarization in antiferromagnetic materials. In this work, we propose a general scheme that can be achieved easily in experiments to break the P T joint symmetry of antiferromagnetic structures, that is, introducing an out-of-plane potential gradient to realize spin–valley splitting and spontaneous valley polarization. In combination of the model analysis and first-principles calculations, we translate the concept into Mn2P2X3Y3 monolayers and clarify the valley-related physics. It is obvious that our finding significantly extends the scope of valleytronics in both theory and experiments. [ABSTRACT FROM AUTHOR]

Graphene nanoribbons (GNRs) and nanographenes synthesized by on‐surface reactions using tailor‐made molecular precursors offer an ideal playground for a study of magnetism towards nano‐spintronics. Although the zigzag edge of GNRs has been known to host magnetism, the underlying metal substrates usually veil the edge‐induced Kondo effect. Here, we report the on‐surface synthesis of unprecedented, π‐extended 7‐armchair GNRs using 7‐bromo‐12‐(10‐bromoanthracen‐9‐yl)tetraphene as the precursor. Characterization by scanning tunneling microscopy/spectroscopy revealed unique rearrangement reactions leading to pentagon‐ or pentagon/heptagon‐incorporated, nonplanar zigzag termini, which demonstrated Kondo resonances even on bare Au(111). Density functional theory calculations indicate that the nonplanar structure significantly reduces the interaction between the zigzag terminus and the Au(111) surface, leading to a recovery of the spin localization of the zigzag edge. Such a distortion of planar GNR structures offers a degree of freedom to control the magnetism on metal substrates. [ABSTRACT FROM AUTHOR]

Molecular oxygen (O2) activation technology is of great significance in environmental purification due to its eco‐friendly operation and cost‐effective nature. However, the activation of O2 is limited by spin‐forbidden transitions, and efficient molecular oxygen activation depends on electronic behavior and surface adsorption. Herein, we prepared cationic defect‐rich Bi4Ti3O12 (BTO‐MV2) catalysts containing Ti vacancies (VTi) for O2 activation in water purification. The VTi on BTO nanosheets can induce electron spin polarization, increasing the number of spin‐down photogenerated electrons and reducing the recombination of electron‐hole pairs. An active surface VTi is also formed, serving as a center for adsorbing O2 and extracting electrons, effectively generating ⋅OH, O2.− and 1O2. The degradation rate constant of tetracycline achieved by BTO‐MV2 is 3.3 times faster than BTO, indicating a satisfactory prospect for practical application. This work provides an efficient pathway to activate molecular oxygen by constructing new active sites through cationic vacancy modification technology. [ABSTRACT FROM AUTHOR]

Electric-field control of spin polarization of electrons during injection into InGaAs quantum dots (QDs) was studied via circularly polarized time-resolved photoluminescence. Electric-field modulation of optical spin polarization in QDs will play a key role in future progress of semiconductor opto-spintronics. The tuning of band potentials by applying external electric fields can not only affect spin-injection efficiencies but also switch dominant spin-injection layers. In this study, we developed a QD-based electric-field-effect optical spin device with two different spin-injection layers, which consisted of a GaAs and GaAs/Al0.15Ga0.85As superlattice (SL) barriers. The bias-voltage modulation of the optical spin polarization in QDs was demonstrated by changing the spin polarization degree of electrons injected from these barriers into the QD via the electric-field switching of the spin-injection layers. This was achieved by exploiting the difference in spin relaxation properties between bulk GaAs and the SL. This proposed structure, which comprised of one luminescent layer and two spin-injection layers, is highly scalable because the modulation range of optical spin polarization can be enhanced by changing the combination of spin-injection layers, as well as the material used and its layer thickness. [ABSTRACT FROM AUTHOR]

Molecular oxygen (O2) activation technology is of great significance in environmental purification due to its eco‐friendly operation and cost‐effective nature. However, the activation of O2 is limited by spin‐forbidden transitions, and efficient molecular oxygen activation depends on electronic behavior and surface adsorption. Herein, we prepared cationic defect‐rich Bi4Ti3O12 (BTO‐MV2) catalysts containing Ti vacancies (VTi) for O2 activation in water purification. The VTi on BTO nanosheets can induce electron spin polarization, increasing the number of spin‐down photogenerated electrons and reducing the recombination of electron‐hole pairs. An active surface VTi is also formed, serving as a center for adsorbing O2 and extracting electrons, effectively generating ⋅OH, O2⋅− and 1O2. The degradation rate constant of tetracycline achieved by BTO‐MV2 is 3.3 times faster than BTO, indicating a satisfactory prospect for practical application. This work provides an efficient pathway to activate molecular oxygen by constructing new active sites through cationic vacancy modification technology. [ABSTRACT FROM AUTHOR]

Defects play significant roles in spin-current-related physical processes in intrinsic ferromagnetic semiconductors (FMSs), which are great promise for spintronics applications. However, current defect calculation methods cannot be used to investigate charged defects in FMSs due to the spin polarization of both the charged defect states and ionized carriers, which is not well treated in current defect calculation methods. In order to solve this problem, we propose a spin-distinguishable charge correction (SDCC) method that uses spin-polarized band edge charge density instead of spin-unpolarized uniform background charge density as the compensating charge for charged defects. We apply our method to study the defect properties of CrI3 monolayer and find it can be doped n-type under the Cr-rich growth condition but difficult to be doped p-type. The SDCC method proposed here is generally suitable for all FMSs, which will be useful for the studies of defect properties of magnetic semiconductors. [ABSTRACT FROM AUTHOR]

Here, we report the experimental investigations on magnetic (spin polarization and exchange bias) and transport (spin-flip and spin-flop) properties of Co2FeSi Heusler compound at cryo temperature and high magnetic field. The spin cluster characteristic of the material is revealed by the M[T] curve of the ZFC, FC, and FW cycles. This can exhibit spin polarization behavior of anti-ferromagnetism (AFM) at 30–70 K. Furthermore, at a critical field of 0.2 T, AFM transforms into ferromagnetic (FM) and on further increasing the magnetic field, the spin polarization region becomes linear due to perseverance of FM behavior. The isothermal magnetization [M(H)] are also evaluated at different temperatures and AFM to FM transition has been observed at various applied magnetic fields. These magnetic measurements are used to determine exchange bias [EB] parameters such as HE, HC, and Mr both at low and room temperature. The resistivity [ρ(T)] has been measured at 0 and 5 T field, which explain the increasing trend of metallic nature at cooling cycle and also provides a clear evidence of magnonic, phononic resistivity and spin-flip scattering. [ABSTRACT FROM AUTHOR]

Two-dimensional ferromagnetic (FM) half-metals are highly desirable for the development of multifunctional spintronic nano-devices due to their 100% spin polarization and possible interesting single-spin electronic states. Herein, using first-principles calculations based on density functional theory (DFT) with the Perdew–Burke–Ernzerhof (PBE) functional, we demonstrate that the MnNCl monolayer is a promising FM half-metal for spintronics. Specifically, we systematically investigated its mechanical, magnetic, and electronic properties. The results reveal that the MnNCl monolayer has superb mechanic, dynamic, and thermal (ab initio molecular dynamics (AIMD) simulation at 900 K) stability. More importantly, its intrinsic FM ground state has a large magnetic moment (6.16 μB), a large magnet anisotropy energy (184.5 μeV), an ultra-high Curie temperature (952 K), and a wide direct band gap (3.10 eV) in the spin-down channel. Furthermore, by applying biaxial strain, the MnNCl monolayer can still maintain its half-metallic properties and shows an enhancement of magnetic properties. These findings establish a promising new two-dimensional (2D) magnetic half-metal material, which should expand the library of 2D magnetic materials. [ABSTRACT FROM AUTHOR]

In this work, the electronic and magnetic features of the Sc2MnSi bulk, surfaces, and the interface with the semiconductor CdTe (111) were thoroughly researched using the first-principles calculations. The Sc2MnSi alloy with equilibrium lattice constant of 6.34 Å shows half-metallic (HM) property. This alloy exhibits an energy gap and a HM gap of 0.54 and 0.12 eV, respectively. The density of states results confirm the existence of the half-metallicity property for the Sc2MnSi component at SiSc(2)-(001), Sc(2)-, and Si-(111) surfaces while this property is not revealed at Sc(1)-, Mn-terminated (111), Sc(1)Mn-terminated (001), and Sc2MnSi (110) surfaces for the same component. In addition, in the case of Sc2MnSi/CdTe interface, it is noted that Cd-Si connection does not reveal the half-metallicity feature, while the Si-Te shape exhibits a 100% spin polarization, thus preserving the half-metallicity. Furthermore, the Si-Te shape is more stable than the others, according to the interfacial adhesion energy. [ABSTRACT FROM AUTHOR]

Heusler compounds have generated significant interest in spintronics due to their unique features. The structural stability, electronic structure, magnetic, and elastic properties of Heusler alloys VXRh2 (X = Sn, Ge, and Si) are investigated using first‐principles calculations of density functional theory in the Quantum Espresso code. The alloys exhibit three magnetic states (nonmagnetic, ferromagnetic, and ferrimagnetic) and several structural phases (face centered cubic (FCC) and tetragonal). It is found that pressures below 0 GPa produce the FCC phase, while greater pressures produce two tetragonal phases. VSnRh2 is a ferromagnetic metal, while VSiRh2 and VGeRh2 exhibit excellent half‐metallic ferromagnetism. The equilibrium lattice constants of VSiRh2 and VGeRh2 are stable against changes, making these Heusler alloys ideal for spintronic devices. Elastic constant computations show that compounds are mechanically stable. [ABSTRACT FROM AUTHOR]

[Display omitted] • Improving CoPc catalyst performance by identifying potential atomic-style linkers. • Calculations suggest improved CO 2 ERR performance for the NH, PH and S linkers. • Unoccupied spin-down d z 2 orbital components facilitate initial CO 2 adsorption. • Contrary to previous experiments, the NH 2 linker shows weak bonding to CoPc. We investigate the CO 2 electroreduction reaction (CO 2 ERR) using first principles calculations, for the active site tuning of cobalt phthalocyanine (CoPc) via distinct atomic linker species which immobilize CoPc on a carbon nanotube (CNT) substrate. Eight different linker species are studied, along with the effect of linker hydrogenation. Superior reaction performance is predicted for the NH, S and PH linkers, which show activated CO 2 adsorption. This results from spin polarization causing unoccupied d z 2 spin-down states of the cobalt active site at, or above, the Fermi level. Using an 'on-catalyst' reaction scheme, calculated activation barriers for COOH formation and CO desorption are lower for the CoPc-PH-CNT system compared to the CoPc-NH-CNT system and CoPc remains attached to PH-CNT throughout the reaction. We thus expect the PH linker system to have similar or better CO 2 ERR performance compared to the NH and S linker systems but at a slightly higher electrode potential. [ABSTRACT FROM AUTHOR]

The article offers information on the spin transport–driven ultrafast magnetization dynamics in a Gadolinium (Gd)/iron (Fe) bilayer. It further discusses that Laser-induced spin transport, a key ingredient in ultrafast spin dynamics; using time- and spin-resolved photoemission spectroscopy to study an antiferromagnetically coupled Gd/Fe bilayer; and the spin transport leads to an ultrafast drop of the spin polarization at the Gd surface.

We used the density functional theory with spin polarization to investigate multifunctional properties of the Sm-doped BaTiO3 system (Ba1–xSmxTiO3). The self-consistent calculation results were used to analyze the ferromagnetic and dielectric properties. The spontaneous electric polarization was estimated from the King-Smith and Vanderbilt theory and 1s core-hole absorbing atom was used to calculate the oxygen K-edge XANES spectra. The Hubbard correction has been considered over the rare-earth f-electrons. Results for x = 0.125 revealed a narrow band-gap energy, showing an enhanced ferroelectric character, with a spontaneous polarization higher than the reported for the pure tetragonal BaTiO3. On the other hand, the magnetic properties have been also confirmed, with a total magnetization value around 5.90 µB/cell, which have been mainly ascribed to the inclusion of the Sm cation into the BT crystalline structure. [ABSTRACT FROM AUTHOR]

The inclusion of La-Mn vacancies in LaMnO3 nanoparticles leads to a noticeable change in conductivity behavior. The sample retains its overall insulator characteristic, with a typical thermal activation mechanism at high temperatures, but it presents high magnetoconductivity below 200 K. The activation energy decreases linearly with the square of the reduced magnetization and vanishes when the sample is magnetized at saturation. Therefore, it turns out that electron hopping between Mn3+ and Mn4+ largely contributes to the conductivity below the Curie temperature. The influence of the applied magnetic field on conductivity also supports the hypothesis of hopping contribution, and the electric behavior can be explained as being due to an increase in the hopping probability via spin alignment. [ABSTRACT FROM AUTHOR]

ZnCoO:H and ZnCoAlO:H films were synthesized by radio frequency magnetron sputtering in a (1 − x)Ar + xH2 mixed atmosphere with x = 0.2–0.5. The films contain different amounts of metallic Co particles (from 7.6% and higher) ~4–7 nm in size. The magnetic and magneto-optical (MO) behavior of the films was analyzed in combination with their structural data. The samples exhibit high values of magnetization (up to 377 emu/cm3) and MO response at room temperature. Two situations are considered: (1) the film magnetism is associated only with isolated metal particles and (2) magnetism is present both in the oxide matrix and in metal inclusions. It has been established that the formation mechanism of the magnetic structure of ZnO:Co2+ is due to the spin-polarized conduction electrons of metal particles and zinc vacancies. It was also found that in the presence of two magnetic components in the films, these components are exchange-coupled. In this case, the exchange coupling generates a high spin polarization of the films. The spin-dependent transport properties of the samples have been studied. A high value of the negative magnetoresistance of the films at room temperature (~4%) was found. This behavior was explained in terms of the giant magnetoresistance model. Thus, the ZnCoO:H and ZnCoAlO:H films with high spin polarization can be considered as sources of spin injection. [ABSTRACT FROM AUTHOR]