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Combining theory and computation, we explore the Goos–Hänchen (GH) effect for electrons in a single-layered semiconductor microstructure (SLSM) modulated by Dresselhaus spin–orbit coupling (SOC). GH displacement depends on electron spins thanks to Dresselhaus SOC, therefore electron spins can be separated from the space domain and spin-polarized electrons in semiconductors can be realized. Both the magnitude and sign of the spin polarization ratio change with the electron energy, in-plane wave vector, strain engineering and semiconductor layer thickness. The spin polarization ratio approaches a maximum at resonance; however, no electron-spin polarization occurs in the SLSM for a zero in-plane wave vector. More importantly, the spin polarization ratio can be manipulated by strain engineering or semiconductor layer thickness, giving rise to a controllable spatial electron-spin splitter in the field of semiconductor spintronics. [ABSTRACT FROM AUTHOR]

The use of Moore's law appears to be coming to an end due to technological and physical constraints, as complementary metal-oxide semiconductor (CMOS) transistors become smaller and closer to the atomic scale. Therefore, various emerging technologies are being researched as potential successors to traditional CMOS transistors, and one of the most exciting candidates is the magnetoelectric spin-orbit (MESO) device. The MESO device comprises two portions (input and output) and it cascades charge/voltage as input and output signals. In the MESO device's output portion, ferromagnetic (FM) and high-spin-orbit-coupling layers are employed to provide spin-polarized current and charge/voltage output. In this paper, we offer a description and analysis of the operating mechanism of the MESO device's output portion using a spin flow approach and propose a double-FM-layer structure. In the double-FM-layer structure, we implement two FM layers with antiparallel magnetization directions, instead of using a single-FM-layer structure to increase the output charge/voltage. The proposed structure is verified through the Verilog-A compact model. [ABSTRACT FROM AUTHOR]

We theoretically investigate Goos-Hänchen effect for electron in single-layered semiconductor microstructure (SLSM) modulated by Rashba spin–orbit coupling (SOC). Due to the SOC effect, GH displacement is obviously dependent on spins, which allows electron spins to be separated in space dimension and results in spin polarization of electrons in semiconductors. Spin polarization ratio is associated with incident energy, incident direction and in-plane wave vector, e.g., it reaches maximum at resonance, but no spin polarization effect appears at normal incidence. In particular, both magnitude and sign of spin polarization ratio are controlled by external electric field or semiconductor-layer thickness, therefore, a manipulable spatial electron-spin splitter is obtained for semiconductor spintronics device applications.

Considering both Zeeman effect and spin–orbit coupling, we calculate dwell time for electron in single ferromagnetic-stripe device (SFSD), which can be constructed by patterning a nanosized ferromagnetic stripe on the surface of GaAs/AlxGa1-xAs heterostructure. Due to an intrinsic symmetry in the SFSD, dwell time is independent of electron spins, if only Zeeman effect is involved. However, the intrinsic symmetry is broken by spin–orbit coupling, which gives rise to spin-dependent dwell time for electron in the SFSD. As a result, electron spins can be separated in time dimension, which induces an obvious electron-spin polarization effect in the SFSD. Spin polarization ratio can be efficaciously modified by interfacial confining electric-field or strain engineering, which attributes to the dependence of effective potential felt by electron in the SFSD on spin–orbit couplings. Thus, the SFSD can act as a controllable temporal electron-spin splitter, a class of electron-spin polarized sources in semiconductor spintronics.

Low-energy (~ 100eV) electrons have been employed for more than half a century to investigate physical, chemical and electronic phenomena in condensed matter and surface physics. A particular role may be attributed to a purely quantum-mechanical property of the electron-its spin or intrinsic angular momentum. Since the 1970s the electron spin has been indispensable in determining the role of spin-dependent interactions, such as exchange interaction and spin-orbit coupling and their consequences. Most recently, the aspect of topology and its role in condensed matter systems has given a new drive to the investigation of the electron spin and spin textures in such materials. New results on time-dependent ultrafast phenomena may become available by the availability of new intense lasers and laser-driven sources. [ABSTRACT FROM AUTHOR]

Low-energy (∼100eV) electrons have been employed for more than half a century to investigate physical, chemical and electronic phenomena in condensed matter and surface physics. A particular role may be attributed to a purely quantum-mechanical property of the electron–its spin or intrinsic angular momentum. Since the 1970s the electron spin has been indispensable in determining the role of spin-dependent interactions, such as exchange interaction and spin-orbit coupling and their consequences. Most recently, the aspect of topology and its role in condensed matter systems has given a new drive to the investigation of the electron spin and spin textures in such materials. New results on time-dependent ultrafast phenomena may become available by the availability of new intense lasers and laser-driven sources.

Herein, the synthesis, structure, room temperature phosphorescence, and magnetic chiroptical properties of phosphoramides 1‐6 with donor–acceptor architecture are reported.5). The electronic interactions between donor phenothiazine (PTZ) and acceptor (C6H5)n‐P = X (n = 1, 2; X = O, S, and Se)moieties in 1–6 are modulated by varying the number of donor units. The Lewis acidity of the phosphorus center is controlled by the nature of heteroatoms and the number of phenyl moieties attached to it. All compounds exhibit phosphorescence in the solid state under ambient conditions with a photoluminescence lifetime in the millisecond range (≈8–40 ms). The energy of the phosphorescence bands and their excited state lifetimes are governed by the P=X units. The phosphorescence features observed for 1–6 are in complete contrast to the observations noted for (PTZ)3P = X (X = O, S, and Se), where the phosphorescence process is completely controlled by the PTZ moiety, and there is a negligible contribution from the P = X moiety. Thus, the present and earlier studies together reveal that the steric crowding and the number of C6H5 moieties around the P = X unit play a crucial role in controlling the electronic coupling between the donor and acceptor moieties in phosphoramides containing non‐planar donor moieties. Furthermore, for the first time, the magnetic chiroptical properties of achiral phosphoramides 1–6, exhibiting a luminescence dissymmetry factor (gMCPL) in the order of 10−3 (≈4.0 × 10−3–7.4 × 10−3) are demonstrated. [ABSTRACT FROM AUTHOR]

In recent years, pure organic room‐temperature phosphorescence (RTP) with highly efficient and long‐persistent afterglow has drawn substantial awareness. Commonly, spin‐orbit coupling can be improved by introducing heavy atoms into pure‐organic molecules. However, this strategy will simultaneously increase the radiative and non‐radiative transition rate, further resulting in dramatic decreases in the excited state lifetime and afterglow duration. Here in this work, a highly symmetric bird‐like structure tetraphenylene (TeP), and its three symmetrical halogenated derivatives (TeP−F, TeP−Cl and TeP−Br) are synthesized, while their RTP properties and mechanisms are systematically investigated by both theoretical and experimental approaches. As the results, the rigid, highly twisted conformation of TeP restricts the non‐radiative processes of RTP and gives rise to the enhancement of electron‐exchange, which can contribute to the RTP radiation process. Despite the faint RTP of the bromine and chlorine‐substituted ones (TeP−Br, TeP−Cl), the fluoro‐substituted TeP−F exhibited a long phosphorescent lifetime up to 890 ms, corresponding to an extremely long RTP afterglow over 8 s, which could be incorporated into the best series of non‐heavy‐atom RTP materials reported in previous literature. [ABSTRACT FROM AUTHOR]

In this paper, we theoretically investigate how to control spin filtering via a δ -doping for electrons in a magnetically and electrically modulated semiconductor nanostructure (MEMSN), which can be realized by patterning a ferromagnetic (FM) stripe and a Schottky-metal (SM) stripe on top and bottom of GaAs/AlxGa 1 − x As heterostructure in experiments, respectively. A considerable spin filtering effect still exists because of spin–orbit coupling (SOC), even if a δ -doping is included. Moreover, spin polarization ratio can be manipulated by δ -doping, which may lead to a structurally-controllable electron-spin filter for semiconductor spintronics. [ABSTRACT FROM AUTHOR]

• GH effect is studied in SLSN modulated by Rashba SOC. • GH displacement depends on electron spins and an evident spin polarization appears. • Spin polarization ratio is tuned by external electric field or semiconductor-layer thickness. • A controllable spatial electron-spin splitter is obtained. We theoretically investigate Goos-Hänchen effect for electron in single-layered semiconductor microstructure (SLSM) modulated by Rashba spin–orbit coupling (SOC). Due to the SOC effect, GH displacement is obviously dependent on spins, which allows electron spins to be separated in space dimension and results in spin polarization of electrons in semiconductors. Spin polarization ratio is associated with incident energy, incident direction and in-plane wave vector, e.g., it reaches maximum at resonance, but no spin polarization effect appears at normal incidence. In particular, both magnitude and sign of spin polarization ratio are controlled by external electric field or semiconductor-layer thickness, therefore, a manipulable spatial electron-spin splitter is obtained for semiconductor spintronics device applications. [ABSTRACT FROM AUTHOR]

Based on a double-layered semiconductor nanostructure (DLSN)-InSb/GaSb, we propose a controllable electron-spin filter for spintronics device applications. Electron-spin polarization is induced by Rashba spin-orbit coupling inside the DLSN. Both magnitude and sign of spin polarization ratio can be manipulated by externally-applied electric field or the semiconductor-layer thickness. [ABSTRACT FROM AUTHOR]

While traditionally considered a deleterious effect in quantum dot spin qubits, the spin-orbit interaction is recently being revisited as it allows for rapid coherent control by on-chip AC electric fields. For electrons in bulk silicon, spin-orbit coupling (SOC) is intrinsically weak, however, it can be enhanced at surfaces and interfaces, or through atomic placement. Here it is showed that the strength of the spin-orbit coupling can be locally enhanced by more than two orders of magnitude in the manybody wave functions of multi-donor quantum dots compared to a single donor, reaching strengths so far only reported for holes or two-donor system with certain symmetry. These findings may provide a pathway toward all-electrical control of donor-bound spins in silicon using electric dipole spin resonance (EDSR)., (© 2024 Wiley‐VCH GmbH.)

In this paper, we study the structural, electronic and optical properties of the inorganic solar perovskites XPbBr3 (X = Li or Na). We applied the two methods: the density-functional theory (DFT) and time-dependent density-functional theory (TDDFT). In fact, we performed the DFT method using the Quantum Espresso package. Also, the total energies of the studied inorganic solar perovskites XPbBr3 (X = Li or Na) have been deduced as a function of the lattice parameter a (Å). The two calculation methods have been carried out under the GGA-PBE and GGA-PBESol approximations. Moreover, the total and partial density of states (DOS) and the band structure of the studied compounds have been presented and discussed for the two cases: with and without the spin-orbit coupling (SOC) approximation. In addition, the DFT and TDDFT have been explored in order to elaborate the structural, the electronic and the optical properties of the inorganic perovskite CsPbI3 material. [ABSTRACT FROM AUTHOR]

• Dwell time and spin polarization for electron in the SFSD is explored theoretically. • No spin polarization occurs in SFSD due to an intrinsic symmetry. • Due to Rashba or Dresselhaus SOC dwell time depends on electron spins. • An obvious electron-spin polarization effect appears in the SFSD. • The SFSD acts as a temporal electron-spin splitter. Considering both Zeeman effect and spin–orbit coupling, we calculate dwell time for electron in single ferromagnetic-stripe device (SFSD), which can be constructed by patterning a nanosized ferromagnetic stripe on the surface of GaAs/Al x Ga 1-x As heterostructure. Due to an intrinsic symmetry in the SFSD, dwell time is independent of electron spins, if only Zeeman effect is involved. However, the intrinsic symmetry is broken by spin–orbit coupling, which gives rise to spin-dependent dwell time for electron in the SFSD. As a result, electron spins can be separated in time dimension, which induces an obvious electron-spin polarization effect in the SFSD. Spin polarization ratio can be efficaciously modified by interfacial confining electric-field or strain engineering, which attributes to the dependence of effective potential felt by electron in the SFSD on spin–orbit couplings. Thus, the SFSD can act as a controllable temporal electron-spin splitter, a class of electron-spin polarized sources in semiconductor spintronics. [ABSTRACT FROM AUTHOR]

A spin thermoelectric (STE) generator is composed of a thin paramagnetic metal (PM) layer, ferrimagnetic insulator (FMI) and PM/FMI bilayer interface. Various studies have been carried out on improving the characteristics of each part of this structure in order to raise the STE voltage $V_{\mathrm {STE}}$. We investigated the substitution of bismuth for yttrium and aluminum for iron to observe the characteristic changes in $V_{\mathrm {STE}}$. FMI films of epitaxial Bi-substituted iron garnets exhibit large growth-induced magnetic anisotropy perpendicular to the film surface. This anisotropy increases the magnetic damping $\alpha $ in the FMI, and the values of $\alpha $ increase with increasing Bi content. As a result, a large rise in STE voltage was observed. We report the rise in $V_{\mathrm {STE}}$ observed in an STE generator incorporating Bi-substituted yttrium iron garnet (YIG) films grown by liquid phase epitaxy (LPE) and explain the origin of the voltage rise based on the results of ferromagnetic resonance measurements. To comprehensively examine the effect of substitution on LPE YIG films, the $V_{\mathrm {STE}}$ values observed in STE generators incorporating Al-substituted YIG films are also presented. [ABSTRACT FROM AUTHOR]

The study of phonon dynamics and its interplay with magnetic ordering is crucial for understanding the unique quantum phases in the pyrochlore iridates. Here, through inelastic x-ray scattering on a single crystal sample of the pyrochlore iridate Eu 2 Ir 2 O 7 , we map out the phonon excitation spectra in Eu 2 Ir 2 O 7 and compare them with the theoretical phonon spectra calculated using the density functional theory. Possible phonon renormalization across the magnetic long-range order transition is observed in our experiments, which is consistent with the results of the previous Raman scattering experiments., (© 2024 IOP Publishing Ltd.)

The normal spinel MnFe2O4 is investigated employing density functional theory calculations using the generalized gradient approximation approach. Here, we address the effect of volume strain on the electronic and magnetic properties of MnFe2O4. We give special emphasis on the strain-induced effect in the magnetocrystalline anisotropy energy (MAE). We observe that compressive strain reduces the magnitude of MAE and leading toward uniaxial symmetry, whereas extensive strain favors planar anisotropy. The site-decomposed orbital anisotropy indicates that B-site atoms largely contribute to the MAE than the A-site atoms. Combined with its half-metallicity and tunable MAE, our results imply a wide range of scientific and technological applications. [ABSTRACT FROM AUTHOR]

Realizing rich topological elements in topological materials has attracted increasing attention in the fields of chemistry, physics, and materials science. Topological semimetals/metals are classified into three main types: nodal-point, nodal-line, and nodal-surface types with zero-, one-, and two-dimensional topological elements, respectively. This study reports that XPt (X = Sc, Y, La) intermetallic compounds are topological metals with opened and closed nodal lines, and triply degenerate nodal points (TNPs) when the spin–orbit coupling (SOC) is ignored. Based on the calculated phonon dispersions, one can find that ScPt and YPt are dynamically stable whereas LaPt is not. When SOC is added, the one-dimensional nodal line and zero-dimensional TNPs disappear. Interestingly, a new zero-dimensional topological element, that is, Dirac points with 4-fold degenerate isolated band crossings with linear band dispersion appear. The proposed materials can be considered a good platform to realize zero- and one-dimensional topological elements in a single compound and to study the relationship between zero- and one-dimensional topological elements.

We present an implementation of spin–orbit coupling (SOC) for density functional theory band structure calculations that makes use of Gaussian basis sets. It is based on the explicit evaluation of SOC matrix elements, both the radial and angular parts. For all-electron basis sets, where the full nodal structure is present in the basis elements, the results are in good agreement with well-established implementations such as VASP. For more practical pseudopotential basis sets, which lack nodal structure, an ad-hoc increase of the effective nuclear potential helps to capture all relevant band structure variations induced by SOC. In this work, the non-relativistic or scalar-relativistic Kohn–Sham Hamiltonian is obtained from the CRYSTAL code and the SOC term is added a posteriori. As an example, we apply this method to the Bi(111) monolayer, a paradigmatic 2D topological insulator, and to mono- and multilayer Sb(111) (also known as antimonene), the former being a trivial semiconductor and the latter a topological semimetal featuring topologically protected surface states.

Here, we outline magnetoelectric (ME) device concepts based on the voltage control of the interface magnetism of an ME antiferromagnet gate dielectric formed on a very thin semiconductor channel with large spin-orbit coupling (SOC). The emphasis of the ME spin field-effect transistors (ME spin FET) is on an antiferromagnet spin-orbit read logic device and a ME spin-FET multiplexer. Both spin-FET schemes exploit the strong SOC in the semiconducting channel materials but remain dependent on the voltage-induced switching of an ME, so that the switching time is limited only by the switching dynamics of the ME. The induced exchange field spin polarizes the channel material, breaks time-reversal symmetry, and results in the preferential charge transport direction, due to the spin-orbit-driven spin-momentum locking. These devices could provide reliable room temperature operation with large on/off ratios, well beyond what can be achieved using magnetic tunnel junctions. All of the proposed device spintronic functionalities without the need to switch a ferromagnet, yielding a faster writing speed (~10 ps) at a lower cost in energy (~10 aJ), excellent temperature stability (operational up to 400 K or above), and requiring far fewer device elements (transistor equivalents) than CMOS.

Graphical abstract Highlights • With the help of first-principles calculations, we propose a new type of two dimensional (2D) topological insulator BiB with bilayer hexagonal lattice. • The spin-orbit coupling will turn this 2D material into topological insulators with nontrivial edge states. • Surprisingly, two mechanisms, including crystal field and strong SOC, induce two band inversions and manipulate the low energy electronic states simultaneously. • The BiB provides a fertile platform for studying the interactions between the two different mechanisms in the same topological insulator. Abstract With the help of first-principles calculations, we propose a new type of two dimensional (2D) topological insulator BiB with bilayer hexagonal lattice. Its dynamic stability was confirmed by the phonon spectrum. When spin-orbit coupling (SOC) effect is not considered, the low energy electronic states around the Fermi level show metallic characteristics. However, the SOC will induce a global band gap and turn this 2D material into topological insulators with nontrivial edge states. Surprisingly, two mechanisms, including crystal field and strong SOC, induce two band inversions and manipulate the low energy electronic states simultaneously. The BiB provides a fertile platform for studying the interactions between the two different mechanisms in the same topological insulator. Moreover, the sizable global nontrivial band gap indicates its high working temperature. [ABSTRACT FROM AUTHOR]

Based on a magnetically confined GaAs/AlxGa1–xAs microstructure modulated by spin-orbit coupling (SOC), we propose a controllable electron-spin filter for spintronics applications. This device operates due to both Zeeman interaction and Rashba or Dresselhaus SOC. Its spin polarization can be tuned by changing interfacial confining electric field or engineering strain. [ABSTRACT FROM AUTHOR]

Spin-orbit coupling (SOC) in graphene can be greatly enhanced by proximity coupling it to transition metal dichalcogenides (TMDs) such as WSe2. We find that the strength of the acquired SOC in graphene depends on the stacking order of the heterostructures when using hexagonal boron nitride (h-BN) as the capping layer, i.e., SiO2/graphene/WSe2/h-BN exhibiting stronger SOC than SiO2/WSe2/graphene/h-BN. We utilize photoluminescence (PL) as an indicator to characterize the interaction between graphene and monolayer WSe2 grown by chemical vapor deposition. We observe much stronger PL quenching in the SiO2/graphene/WSe2/h-BN stack than in the SiO2/WSe2/graphene/h-BN stack and, correspondingly, a much larger weak antilocalization (WAL) effect or stronger induced SOC in the former than in the latter. We attribute these two effects to the interlayer distance between graphene and WSe2, which depends on whether graphene is in immediate contact with h-BN. Our observations and hypothesis are further supported by first-principles calculations, which reveal a clear difference in the interlayer distance between graphene and WSe2 in these two stacks. [ABSTRACT FROM AUTHOR]

A theoretical study on a series of neutral heteroleptic Cu(I) complexes with different azole-pyridine-based N^N ligands has been presented to get insight into the effect of various nitrogen atoms in the azole ring on photophysical properties. The results reveal that the highest occupied molecular orbital (HOMO) levels and the emission wavelengths of these complexes are mainly governed by the nitrogen atom number in azole ring. With the increasing number of nitrogen atom, the electron density distribution of HOMO gradually extend from the N^N ligand to the whole molecule, meanwhile, the improved contribution from Cu(d) orbits in HOMO results in an effective mixing of various charge transfermodes, and hence, the fast radiative decay(kr) and the slow non-radiative decay rate(knr) are achieved. The photoluminescence quantum yield (PLQY) show an apparent dependence on the nitrogen atom number in the five-membered nitrogen heterocycles. However, the increasing number of nitrogen atoms is not necessary for increasing PLQY. The complex 3 with 1,2,4-triazole-pyridine-based N^N ligands is considered to be a potential emitter with high phosphorescence efficiency. Finally, we hope that our investigations will contribute to systematical understanding and guiding for material molecular engineering. [ABSTRACT FROM AUTHOR]

In this report, the electronic structure, mechanical stability, optoelectronic, thermoelectric and photocatalytic response of inorganic halide perovskites Rb 2 BCl 6 (B= Pb, Ti) have been simulated first time by using density functional theory (DFT). Modified Becke-Johnson (mBJ) potential along with spin-orbit coupling (SOC) effect is applied for accurate calculations. The calculated ground-state lattice parameters, negative formation energy values and positive phonon frequencies endorse the stability of both compounds. The band structure plots display the semiconductor character of both perovskites. The mechanical stability has been determined with the Bulk and Young modulus, Poisson ratio, along with the calculation of elastic constants. The calculated optical response reveals a high dielectric constant and absorption coefficient with low reflectivity. These compounds are revealed to have a higher figure of merit (ZT) than the typical metal halide perovskites with the values of 0.732 and 0.72 for Rb 2 PbCl 6 and 0.724 and 0.71 for Rb 2 TiCl 6 at 800K with mBJ and mBJ+SOC, respectively. The Seebeck coefficient and figure of merit present good values at high temperatures. The photocatalytic activity has shown the water-splitting ability of Rb 2 TiCl 6. The overall analysis of the calculated properties shows that the studied halide perovskites are suitable for optoelectronic, thermoelectric and photocatalytic applications. [ABSTRACT FROM AUTHOR]

We consider possibilities to control dynamics of solitons of two types, maintained by the combination of cubic attraction and spin-orbit coupling (SOC) in a two-component system, namely, semi-dipoles (SDs) and mixed modes (MMs), by making the relative strength of the cross-attraction, γ , a function of time periodically oscillating around the critical value, γ = 1 , which is an SD/MM stability boundary in the static system. The structure of SDs is represented by the combination of a fundamental soliton in one component and localized dipole mode in the other, while MMs combine fundamental and dipole terms in each component. Systematic numerical analysis reveals a finite bistability region for the SDs and MMs around γ = 1 , which does not exist in the absence of the periodic temporal modulation (“management”), as well as emergence of specific instability troughs and stability tongues for the solitons of both types, which may be explained as manifestations of resonances between the time-periodic modulation and intrinsic modes of the solitons. The system can be implemented in Bose-Einstein condensates (BECs), and emulated in nonlinear optical waveguides.

The reaction mechanism of uranium atom with acetonitrile molecule has been systematically studied on the quintet and triplet spin-state potential energy surfaces (PESs) at B3LYP level of density functional theory. Reaction site prediction and bonding evolution were analyzed using different methods. Crossing seams and possible spin inversion processes between different PESs are discussed by means of spin-orbit coupling (SOC) calculations. The results show that there are three crossing points in the reaction, which appear in the process of capturing hydrogen atom. Larger SOC constant (1545.80 cm) and intersystem crossing (ISC) probability (< P > = 0.72) between quintet and triplet indicate that the effective ISC would occur in the vicinity of the minimum energy crossing points. [ABSTRACT FROM AUTHOR]

Applying a transverse electric field, we theoretically explore the control of electron-spin filter based on layered semiconductor nanostructure-InSb/In x Ga 1-x As. Because of the electric field dependent effective potential of electron, not only size of spin polarization ratio but also its sign can be manipulated by changing magnitude or direction of applied electric field. An electrically-tunable electron-spin filter can be achieved for spintronics device applications. • Spin polarized transport is studied for electrons through InSb/In x Ga 1-x As/GaSb under a transverse electric field. • Electron-spin polarization is sensitive to applied electric field. • Both magnitude and sign of the spin polarization can be controlled by changing strength or direction of transverse electric field. • This layered semiconductor nanostructure can serve as an electrically-controllable electron-spin filter for spintronics device applications. [ABSTRACT FROM AUTHOR]

The two-state reaction mechanism of the C 2 H 4 catalyzed by HNbN − on the singlet and triplet potential energy surfaces (PESs) is detailed studied by density functional theory (DFT) at the BMK/def2-TZVPD ⋃ TZVP level. A crossing point (CP) appears between the singlet and triplet PESs, and possible spin inversion processes is discussed by spin-orbit coupling (SOC) calculation. The result shows that the SOC is efficient. Where spin multiplicities of the reacting system is changed from the triplet state to the singlet PES near the crossing seam. In addition, the energetically most favorable pathway is discovered. [ABSTRACT FROM AUTHOR]

Shubnikov-de Haas (SdH) oscillation measurements at 1.5 K were carried out for In 0.52 Al 0.48 As/In 0.65 Ga 0.35 As heterostructures with different Si delta-doping concentration and spacer thickness. The dominant zero-magnetic field spin splitting mechanism is attributed to the contribution by the Rashba term due to the structure inversion asymmetry (SIA) in the In 0.65 Ga 0.35 As quantum well. The origin of the beating pattern in the SdH oscillations is investigated through the calculation of the transverse magnetoresistance versus magnetic field B by considering the Zeeman splitting and zero-magnetic field spin splitting in Si delta-doped In 0.65 Ga 0.35 As quantum wells. The good agreement between the theoretical and experimental curves suggest that the origin of beating patterns of the SdH oscillations is due to interplay of Rashba spin splitting, Zeeman splitting and Landau splitting. [ABSTRACT FROM AUTHOR]

The spin-forbidden reaction mechanism of 2-butyne catalyzed by Nb atom has been systematically investigated on different potential energy surfaces (PESs) at the B3LYP level. Besides, spin inversion between surfaces of quartet and doublet states has been discussed by means of spin orbit coupling (SOC) calculations. The result indicates that there is a minimal energy crossing point (MECP) of two adiabatic surfaces in the process of the first C H bond activation. The values of P 1 ISC and P 2 ISC at MECP1 are 0.06 and 0.11, respectively. High probabilities near the crossing seam indicate that the reacting system will change its spin multiplicities from the quartet state to the doublet state. Finally, four H 2 elimination pathways and one CH 4 elimination pathway have been found, and the concerted H 2 -elimination, which leads to Nb(H 2 CCCCH 2 ) + H 2 , is the most favorable pathway. [ABSTRACT FROM AUTHOR]

The potential energy curves (PECs) of the 22 Λ–S states of the phosphorus monoiodide (PI) molecule have been calculated at the level of MRCI+Q method with correlation-consistent quadruple-ζ quality basis set. The spectroscopic constants of the bound states are determined, which well reproduce the available measurements. The metastable a 1 Δ state has been reported for the first time, which lies between the X 3 Σ − and b 1 Σ + states and have much deeper well than the ground state. The R -dependent spin–orbit (SO) matrix elements are calculated with the full-electron Breit–Pauli operator. Based on the SO matrix elements, the perturbations that the 2 3 Π state may suffer from are analyzed in detail. The SOC effect makes the original Λ–S states split into 51 Ω states. In the zero-field splitting of the ground state X 3 Σ − , the spin–spin coupling contribution (2.23 cm −1 ) is found to be much smaller compared to the spin–orbit coupling contribution (50 cm −1 ). The avoided crossings between the Ω states lead to much shallower potential wells and the change of dissociation relationships of the states. The Ω-state wavefunctions are analyzed depending on their Λ–S compositions, showing the strong interactions among several quasidegenerate Λ–S states of the same total SO symmetry. The transition properties including electric dipole ( E 1), magnetic dipole ( M 1), and electric quadrupole ( E 2) transition moments ( TM s), the Franck–Condon factors, the transition probabilities and the radiative lifetimes are computed for the transitions between Ω components of a 1 Δ and b 1 Σ + states and ground state. The transition probabilities induced by the E 1, E 2, and M 1 transitions are evaluated. The E 2 makes little effect on transition probabilities. In contrast, the E 1 transition makes the main contribution to the transition probability and the M 1 transition also brings the influence that cannot be neglected. Finally, the radiative lifetimes are determined with the transition moments including E 1 and M 1. The lifetime of transition (2)0 + –X 1 0 + is evaluated at the level of millisecond, much smaller than that of the transition (2)0 + –X 2 1. [ABSTRACT FROM AUTHOR]

High-levelab initiocalculations have been performed on the PBr radical by using multi-reference configuration interaction method plus Davidson correction (+Q) with correlation-consistent quadruple-ζ quality basis set. The potential energy curves (PECs) of the 22 Λ–S states of PBr have been obtained, most of which are reported for the first time. From the PECs of the bound states, the spectroscopic constants have been determined, in good agreement with the experimental results where available. Due to the large state density, there exhibits complicated interactions in the electronic excited states of PBr. The possible interactions by the spin–orbit coupling (SOC) effect have been discussed based on the evaluatedR-dependent spin–orbit matrix elements. The 51 Ω states, generating from the 22 Λ–S states after taking SOC into account, have been computed. The Λ–S component analysis of the wavefunctions for the Ω states indicates the strong interaction of the Λ–S states especially at the avoided crossing points and near the dissociation limits. Finally, the transition dipole moments of several transitions arising from upper Ω states to the X10+and X21 states and the corresponding radiative lifetimes have been studied. Our calculation results provide new information that should be valuable for further experimental studies on the electronic excited states of the PBr radical. [ABSTRACT FROM AUTHOR]

The gas-phase reaction of C–H bond activation in ethane by CrO 2 + has been investigated using density functional theory (DFT) at the UB3LYP/6-311G(2d,p) level. Our results reveal that the activation process is actually a spin-forbidden reaction. The involved crossing point between the doublet and quartet potential energy surfaces (PES) has been discussed by two well-known methods, i.e., intrinsic reaction coordinate (IRC) approach for crossing point (CP) and Harvey’s algorithm for minimum energy crossing point (MECP). The obtained single ( P 1 ISC = 2.48 × 10 −3 ) and double ( P 1 ISC = 4.95 × 10 −3 ) passes estimated at MECP show that the intersystem crossing (ISC) occurs with a little probability. The C–H bond activation processes should proceed to be endothermic by 73.16 kJ/mol on the doublet surface without any spin change. [ABSTRACT FROM AUTHOR]

Gas-phase CS activation by M (M = Ta, W, Re) was studied by the B3LYP density functional method.The geometries for reactants, transition states, and products were completely optimized. CS activation mediated by M (M = Ta, W, Re) were found to be a spin-forbidden process as a result of the crossing among the multistate energetic profiles. On the basis of the Hammond postulate, this was a typical two-state reactivity reaction. Among the different potential energy surfaces, the crossing points had been explored. The spin-orbit coupling (SOC) was also calculated between the electronic states of different multiplicities at the crossing point to estimate the intersystem crossing probability. For CP1, CP2, and CP4, the computed SOC constants were 80.28, 128.65, and 526.77 cm, which obtained by using one-electron spin-orbit Hamiltonian in Gaussian 09. [ABSTRACT FROM AUTHOR]

The mechanism of the cyclic reaction NO(∑) + CO(∑) → N(∑) + CO(∑) catalyzed by Re has been investigated on quintet and septet potential energy surfaces (PES). The reactions were studied by the B3LYP density functional method and the CCSD(T) theory. The calculated results of different PES show that the reaction proceeds in a two-step manner and spin crossing between different PES occurs. The involving crossing points (CPs) between the quintet and septet PES have been discussed by means of the intrinsic reaction coordinate approach. And the O-atom affinities testified that Re can capture O from NO and transfer O atom to CO in the two spin state, which are thermodynamically allowed. Furthermore, the spin-orbit coupling (SOC) is calculated between electronic states of different multiplicities at the CPs. For CP1 and CP2, the computed SOC constants are 8.34 and 10.09 cm, respectively, obtained by using one-electron spin-orbit Hamiltonian in GAMESS. Therefore, the intersystem crossing at CP1 and CP2 occurs with a little probability because of the small SOC involved. [ABSTRACT FROM AUTHOR]

Exploring a two-dimensional ferromagnetic material with a high Curie temperature and large magnetic anisotropy energy is still challenging. Here, we implement an effective adjustment on the electronic and magnetic properties of VI 3 monolayer by means of first-principles calculation. The results indicate that the most stable structure of VI 3 monolayer is particularly susceptible to the calculation parameter such as Hubbard U and the spin-orbit coupling (SOC). Ultimately, under density functional theory (DFT) +U + SOC (U = 3 eV), the most stable structure of VI 3 monolayer is a ferromagnetic semiconductor with a direct band gap of 0.51 eV, and the predicted Curie temperature (T C) is 29 K. Biaxial strain and carrier doping could not only induce VI 3 monolayer FM-AFM-FM transition, but also effectively increase T C to 123 K under 0.5 electron doping. Meanwhile, carrier hoping realizes the potential ferromagnetic half-metal. Fortunately, in the constructing alloy monolayer, the VTaI 6 monolayer is found a ferromagnetic half-metal under DFT + U (U = 3, 1 eV for V and Ta), and the T C is increased to 74 K. Moreover, VTaI 6 monolayer possesses a large in-plane magnetic anisotropy energy (IMA) and its physical origin is explained in detail based on the second-order perturbation theory. These findings suggest that VI 3 monolayer has a potential application in the spintronics and high-density magnetic storage devices. [Display omitted] • The most stable structure of VI 3 monolayer is very susceptible to the calculation parameters such as Hubbard U value and spin-orbit coupling effect. • Carrier doping can make the VI 3 system generate potential half-metallic characteristics, while biaxial strain maintains its semiconductor properties. • Biaxial strain and carrier doping could not only induce FM-AFM-FM transition, but also carrier doping make T C increase by 3–4 times. • The VTaI 6 monolayer is a FM half-metal and possesses a large in-plane magnetic anisotropy energy (−6.505 meV). [ABSTRACT FROM AUTHOR]

Highlights: [•] Theoretical study of the spin-forbidden reaction of N2O and H2 catalyzed by (n =1, 2). [•] Reactions are typical “two-state reactivity” (TSR) reactions, four crossing points are involved. [•] ISC takes place between high- and low-spin states with a large probability. [•] The energetic span (δE) model was applied in this cycle to obtain some kinetic information. [Copyright &y& Elsevier]

Abstract: The insertion reaction of Zr (4d25s2) into the C–CN bond of CH3CN on the triplet and singlet potential energy surfaces (PESs) has been investigated at the density functional theory (DFT) using the hybrid exchange correlation functional B3LYP and B3PW91 level. The overall reaction is calculated to be exothermic by 54.59kcal/mol. After the nitrile pi-complex, two distinct reaction paths have been found; we have analyzed the crucial activation barriers of the elementary paths 1 and 2 using the activation strain model and the Curtin–Hammett principle (CHP). Crossing points (CPs) between the potential energy surfaces are located, the minimum energy crossing points (MECPs) are obtained using the algorithm in Harvey method and possible spin inversion processes are discussed by means of spin–orbit coupling (SOC) calculations. These theoretical results can act as a guide to further theoretical and experimental researches. [Copyright &y& Elsevier]

Abstract: The potential energy surface (PES) corresponding to the reaction NO2(2A1) with CO(1∑+) catalyzed by Ir+ has been investigated by using density functional theory (DFT). Minimum energy crossing points (MECPs) on the potential energy surfaces are located by using the methods of Harvey et al. The possible spin inversion processes are discussed by means of spin–orbit coupling (SOC) calculations. As a result, the values of the SOC constants at 4/2MECP1 and 5/3MECP2 are 617 and 1187cm−1, respectively. The latter is found to be the energetically favored channel. The energetic span (δE) model coined by Kozuch was applied in this cycle to obtain some kinetic information. The turnover frequency (TOF) determining transition state (TDTS) and TOF determining intermediate (TDI) were confirmed, and the TOF was calculated by the AUTOF program at different temperatures. [Copyright &y& Elsevier]

Abstract: The potential energy surface crossings for reaction between NO2(2A1) and CO(1∑+) catalyzed by Os+ have been investigated using the density functional theory (DFT). Minimum-energy crossing points (MECPs) between the potential energy surfaces and the possible spin inversion process are discussed by means of spin–orbit coupling (SOC) calculations. The latter is found to be the energetically favored channel. The energetic span (δE) model has been applied in this cycle to obtain some kinetic information. TDTS (TOF-determining transition state) and the TDI (TOF-determining intermediate) were confirmed, and TOF (E-representation) was calculated at different temperatures. [Copyright &y& Elsevier]

Abstract: Gas-phase Pt+-catalyzed oxidation of methane by oxygen includes two important and interested cycle reactions. They have been theoretically investigated using density functional theory (DFT) at B3LYP/6-311+G (3df, 3pd) level on their doublet and quartet potential energy surfaces (PESs). Three crossing points between the two potential energy surfaces are located. The possible spin inversion processes are estimated by means of spin–orbit coupling (SOC) calculations. The probability of electronic transition in the vicinity of the minimum energy crossing point (MECP) was treated with Landau–Zener-type theory. Finally, the minimum energy reaction paths were found. The energetic span (δE) model proposed by Kozuch has been applied to reveal the kinetic behavior of the two catalytic cycles. Some other theoretical analyses have been done using natural bonding orbital (NBO) and molecular orbital theory. [Copyright &y& Elsevier]

Abstract: The mechanism of the cyclic reaction catalyzed by Co+ has been investigated on both triplet and quintet potential energy surfaces (PESs). The reactions were studied by the UB3LYP density functional method and the CCSD(T) theory. The calculated results of different spin PES show that the reaction proceeds in a two-step manner and spin crossing between different PES occurs. The involved crossing between the PES has been discussed by means of the intrinsic reaction coordinate approach used by Yoshizawa et al., and the crossing points were located. Furthermore, the spin–orbit coupling (SOC) is calculated between electronic states of different multiplicities at the crossing points to estimate the intersystem crossing probabilities. [Copyright &y& Elsevier]

The two-state mechanism of the reaction of Nb(NH) with NO on the singlet and triplet potential energy surfaces has been investigated at the B3LYP level. Crossing points between the potential energy surfaces have been located using different methods. Analysis of the strain model shows that the singlet state of the four-coordinate (NO)Nb(NH) complex with NO bonded via terminal N atom coordination ( 2) is more stable in the initial stage of reaction, since the bending of the NO fragment [ E(NO) = 86.1 kcal mol] results in an energy splitting of the doubly degenerate LUMO; the low-energy LUMO can now strongly couple with the occupied Nb-localized d orbitals, forming a back-bond and transferring charge ( q = 0.82 e) from Nb(NH) to the NO ligand. Going from 2 to 2, the reacting system changes spin multiplicity near the MECP (minimal energy crossing point) region, which takes place with a spin crossing barrier of 9.6-10.0 kcal mol. Analysis of spin-orbit coupling (SOC) indicates that MECP will produce a significant SOC matrix element. The value of SOC is 111.52 cm, due to the electron shift between two perpendicular ϕ orbitals with the same rotation direction, and the magnitude of the spin-multi-plicity mixing increases in the small energy gap between high- and low-spin states, greatly enhancing the probability of intersystem crossing. The probabilities of single ( P) and double ( P) passes estimated at MECP (SOC = 111.52 cm) are approximately 1.17×10 and 2.32×10, respectively. [ABSTRACT FROM AUTHOR]

Abstract: The insertion reaction of Ce+(4H, 4f15d2) into the N ammonia on the doublet and quartet potential energy surfaces has been investigated at the density functional theory using the hybrid exchange correlation functional B3LYP level. Crossing points between the potential energy surfaces are located using different methods, and possible spin inversion processes are discussed by means of spin–orbit coupling (SOC) calculations. As a result, there is a crossing point between the doublet and the quartet state surfaces. The reacting system will start in the quartet ground state, the change of the spin state probably occurring immediately after the formation of the electrostatic complex intermediate, leading to a significant decrease in the barrier height of 4TS12 from 17.3 to 2.5kcal/mol, and then move on the doublet potential energy surface as the reaction proceeds. The minimum energy crossing point (2/4MECP) is located by using the methods of Harvey et al. On the basis of the calculated SOC value and potential energy surfaces, the estimated probability of ISC (P ISC) at 2/4MECP is approximate 0.214. Additionally, the natural bond orbital (NBO) and natural resonance theory (NRT) analyses have been used to characterize the nature of the bonds for all of the minima and transition states along the optimal reaction paths. On the basis of the obtained results, it is possible to conclude that for the molecules considered the reaction is a spin-forbidden process, this is a typical two-state reactivity (TSR) reaction. These conclusions are consistent with the experimental observations. [Copyright &y& Elsevier]

Abstract: Activation of the C–H bonds in C2H4 by the group 5 metal atoms have been examined systematically using density function theory (DFT, UB3LYP) with the relativistic effective core potential (ECP) of basis sets (SDD) for V, Nb, Ta and the 6-311++G (3df, 3pd) basis set for C and H. The reaction mechanisms have been explored in detail on sextet, quartet and doublet potential energy surfaces. The process involves an intersystem crossing (ISC) between the quartet and doublet state. We have obtained many minimum energy crossing points (MECPs) using the algorithm in Harvey method. These theoretical results can act as a guide to further theoretical and experimental researches. [ABSTRACT FROM AUTHOR]

Abstract: The gas-phase Fe+-mediated cycle reaction N2O (1Σ+)+NH3 (1A1)+O2 →N2 +H2O (1A1)+ cis-HNO2 (1A′) on both sextet and quartet potential energy surfaces (PESs) has been theoretically investigated using density functional theory. Spin inversion between sextet and quartet potential energy surfaces was discussed by using spin–orbit coupling (SOC) calculations. The crossing points and the corresponding minimum energy crossing points have been explored. The probability of hopping in the vicinity of the crossing has been calculated by the Landau–Zener-type model. The energetic span (δE) model has been applied in this cycle to obtain some kinetic information. TOF (E-representation) was calculated at different temperatures. TDTS (TOF-determining transition state) and TDI (TOF-determining intermediate) were confirmed. Finally, the minimum energy reaction path was found. [ABSTRACT FROM AUTHOR]

First-principles calculations on the magnetocrystalline anisotropy (MCA) of Fe3Si have been investigated by means of the all-electron full-potential linearized augmented plane-wave method within general gradient approximation. Calculated MCA constants k1 and k2 are 0.33 and -\0.17\ \mu\eV/Fe, respectively, in consistency with experiment. Easy magnetization axis along the \langle 100\rangle direction was found in a cubic Fe3Si compared to the \langle 110\rangle and \langle 111\rangle magnetization axes. We investigated the strain-dependent MCA energy under tetragonal distortion to predict magnetic easy axis when Fe3Si grows on a substrate. The calculated MCA energies explain quite well experimental results on Fe3Si systems on GaAs(001) and MgO(001). Magnetic moments, elastic constants, and magnetostriction were found to be quite consistent with experiments. [ABSTRACT FROM AUTHOR]

The two-state reaction mechanism of the Pt with NO (CO) on the quartet and doublet potential energy surfaces has been investigated at the B3LYP level. The effect of Pt anion assistance is analyzed using the activation strain model in which the activation energy (Δ Ε) is decomposed into the distortion energies $$ (\Updelta E^{ \ne }_{\text{dist}} ) $$ and the stabilizing transition state (TS) interaction energies $$ (\Updelta E^{ \ne }_{\text{int}} ) $$, namely $$ \Updelta E^{ \ne } = \Updelta E^{ \ne }_{\text{dist}} + \Updelta E^{ \ne }_{\text{int}} $$. The lowering of activation barriers through Pt anion assistance is caused by the TS interaction $$ \Updelta E^{ \ne }_{\text{int}} $$ (−90.7 to −95.6 kcal/mol) becoming more stabilizing. This is attributed to the NO π*-LUMO and Pt d HOMO back-donation interactions. However, the strength of the back-donation interactions has significantly impact on the reaction mechanism. For the Pt anion system, it has very significant back-bonding interaction (NO negative charge of 0.79e), HOMO has 81.5% π* LUMO(NO) character, with 3d orbital contributions of 10.7% from Pt and 7.7% from Pt near the TS4 transition state. This facilitates the bending of the NO molecule, the N-O bond weakening, and an O(P) dissociation without surface crossing. For the Pt cation system, the strength of the charge transfer is weaker, which leads to the diabatic (spin conserving) dissociation of NO: NO(∑) → N(∑) + O(D). The quartet to doublet state transition should occur efficiently near the TS1 due to the larger SOC value calculated of 677.9 cm. Not only will the reaction overcome spin-change-induced barrier (ca. 7 kcal/mol) but also overcome adiabatic barrier (ca. 40.1 kcal/mol).Therefore, the lack of a thermodynamic driving force is an important factor contributing to the low efficiency of the reaction system. [ABSTRACT FROM AUTHOR]