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We study the electron–phonon and Rashba spin–orbit coupling effects on thermodynamic properties of a monolayer graphene under magnetic field. We propose a diagonalization procedure to solve the Fröhlich-type Hamiltonian based on the Lee–Low–Pines theory. The study reveals that, the cyclotron frequency, Debye cut-off wavenumber (DCOW) and Rashba spin–orbit coupling (RSOC) modulate the thermodynamic properties through Tsallis formalism for different substrates. It is also found that RSOC induce a gap formation while dropping the disorder thus rising up the potential application. [ABSTRACT FROM AUTHOR]

Research on new-generation materials to meet the energy needs has begun to attract attention. Recetly, energy storage in materials has become the most researched area. As a result of the reaction of the MAX phase 312 Ti3SiC2 powder with hydrofluoric acid, a new 2D nanosized layered powder called MXene, similar to graphene, was obtained. MXenes, which have been studied in various sectors, especially energy, have attracted the attention of researchers owing to their multilayered structures. When Ti3SiC2 powder was treated with hydrofluoric acid (HF), an accordion-like two-dimensional Ti3C2Tx MXene structure was formed. In MXenes, surface coatings such as -O,-OH, and -F groups, which determine and affect various aspects of 2D materials, such as conductivity, constitute the application area. In this study, Ti3C2(OH)2-O and/or-OH surface terminations were examined using density functional theory (DFT) with the effect of the hydrofluoric acid etching time. Quantum Espresso program was used for DFT calculation. X-ray diffraction (XRD) and scanning electron microscopy (SEM and FESEM) were used to examine the MXenephase Ti3C2Tx powder and first-principles calculations were performed. The structural and electronic properties of MAX and MXene compounds were determined. The spin-orbit effect (SOI) was examined in the electronic structure of MXene. The total and partial densities of states (DOS) with and without spin orbit were calculated. [ABSTRACT FROM AUTHOR]

The g tensor, which determines the reaction of Kramers-degenerate states to an applied magnetic field, is of increasing importance in the current design of spin qubits. It is affected by details of heterostructure composition, disorder, and electric fields, but it inherits much of its structure from the effect of the spin-orbit interaction working at the crystal-lattice level. Here, we uncover interesting symmetry and topological features of g = gL + gS for important valence and conduction bands in silicon, germanium, and gallium arsenide. For all crystals with high (cubic) symmetry, we show that large departures from the nonrelativistic value g = 2 are guaranteed by symmetry. In particular, considering the spin part gS(k), we prove that the scalar function det(gS(k)) must go to zero on closed surfaces in the Brillouin zone, no matter how weak the spin-orbit coupling is. We also prove that for wave vectors k on these surfaces, the Bloch states junki have maximal spin-orbital entanglement. Using tight-binding calculations, we observe that the surfaces det(g(k)) = 0 exhibit many interesting topological features, exhibiting Lifshitz critical points as understood in Fermi-surface theory. [ABSTRACT FROM AUTHOR]

This work reports the magnetic index of aromaticity of cyclophosphazene (c$$ c $$‐P3$$ {}_3 $$N3$$ {}_3 $$H6$$ {}_6 $$) and their halogenated cyclic derivatives: c$$ c $$‐P3$$ {}_3 $$N3$$ {}_3 $$F6$$ {}_6 $$, c$$ c $$‐P3$$ {}_3 $$N3$$ {}_3 $$Cl6$$ {}_6 $$, c$$ c $$‐P3$$ {}_3 $$N3$$ {}_3 $$Br6$$ {}_6 $$, c$$ c $$‐P3$$ {}_3 $$N3$$ {}_3 $$I6$$ {}_6 $$, c$$ c $$‐P3$$ {}_3 $$N3$$ {}_3 $$At6$$ {}_6 $$ and c$$ c $$‐P3$$ {}_3 $$N3$$ {}_3 $$Ts6$$ {}_6 $$. This index, also known as ring‐current strength, is calculated by numerical integration of the magnetically‐induced current density vector field which is generated by a perturbing external magnetic field. Due to the presence of heavy X=Br,I,At$$ \mathrm{X}=\mathrm{Br},\mathrm{I},\mathrm{At} $$ atoms in c$$ c $$‐P3$$ {}_3 $$N3$$ {}_3 $$X6$$ {}_6 $$, important relativistic were expected. Accordingly, all‐electron density functional theory (DFT) calculations were carried out using the four‐component Dirac‐Coulomb (DC) Hamiltonian, including scalar and spin‐orbit relativistic effects. The values were also compared with the corresponding spin‐free (scalar relativistic) ones. [ABSTRACT FROM AUTHOR]

It is well known that the Dresselhaus spin-orbit coupling (SOC) in semiconductor two dimensional electron gases (2DEGs) possesses both linear and cubic in momentum contributions. Nevertheless, the latter is usually neglected in most theoretical studies. However, recent Kerr rotation experiments have revealed a significant enhancement of the cubic Dresselhaus interaction by increasing the drift velocities in 2DEGs hosted in GaAs quantum wells. Here, we present a study of the optical spin Hall conductivity in 2DEGs under the simultaneous presence of Rashba and (linear plus cubic) Dresselhaus SOC. The work was done within the Kubo formalism in linear response. We show that the coexistence of the Rashba and cubic Dresselhaus SOC in 2DEGs promotes a strong anisotropy of the band spin splitting which in turn leads to a very characteristic frequency dependence of the spin Hall conductivity. We find that the spin Hall conductivity response could be very sensible to sizeable cubic-Dresselhaus coupling strength. This may be of relevance for the optical control of spin currents in 2DEGs with non-negligible cubic-Dresselhaus SOC. [ABSTRACT FROM AUTHOR]

We present the behaviors of dynamical transverse spin susceptibilities of undoped phosphorene monolayer using the Green's function approach in the context of Kane–Mele model Hamiltonian. Such dynamical spin susceptibility is proportional to inelastic cross section of neutron beam from the layer. Specially, the effects of magnetic field and spin–orbit coupling strength on the spin excitation modes of phosphorene monolayer are investigated via calculating correlation function of spin density operators. Our results show the increase of magnetic field leads to move the magnetic excitation energy to higher values. Also, the intensity of peaks in inelastic cross section reduces with increase of magnetic field. We also show that applying both uniaxial and biaxial strains causes to decrease the intensity of peaks in dynamical spin susceptibility. Finally the effects of both compressive and tensile strains on frequency dependence of dynamical spin structure factor of phosphorene layer are studied. Moreover, the frequency positions of spin excitation mode of phosphorene layer have been investigated due to the effects of spin orbit coupling strength in details. • The study of dynamical spin susceptility of phosphorene monolayer due to the strain effects. • The effects of spin–orbit coupling on the behaviors of frequency dependence of spin susceptibility. • The investigation of effects of spin orbit coupling on frequency dependence of susceptibility. [ABSTRACT FROM AUTHOR]

Converting charge current into spin current is one of the main mechanisms exploited in spintronics. One prominent example is the Edelstein effect, namely, the generation of a magnetization in response to an external electric field, which can be realized in systems with lack of inversion symmetry. If a system has electrons with an orbital angular momentum character, an orbital magnetization can be generated by the applied electric field, giving rise to the so-called orbital Edelstein effect. Oxide heterostructures are the ideal platform for these effects due to the strong spin–orbit coupling and the lack of inversion symmetries. Beyond a gate-tunable spin Edelstein effect, we predict an orbital Edelstein effect an order of magnitude larger then the spin one at the (111) LaAlO 3 /SrTiO 3 interface for very low and high fillings. We model the material as a bilayer of t 2 g orbitals using a tight-binding approach, whereas transport properties are obtained in the Boltzmann approach. We give an effective model at low filling, which explains the non-trivial behaviour of the Edelstein response, showing that the hybridization between the electronic bands crucially impacts the Edelstein susceptibility. [ABSTRACT FROM AUTHOR]

It is well known that the Dresselhaus spin-orbit coupling (SOC) in semiconductor two dimensional electron gases (2DEGs) possesses both linear and cubic in momentum contributions. Nevertheless, the latter is usually neglected in most theoretical studies. However, recent Kerr rotation experiments have revealed a significant enhancement of the cubic Dresselhaus interaction by increasing the drift velocities in 2DEGs hosted in GaAs quantum wells. Here, we present a study of the optical spin Hall conductivity in 2DEGs under the simultaneous presence of Rashba and (linear plus cubic) Dresselhaus SOC. The work was done within the Kubo formalism in linear response. We show that the coexistence of the Rashba and cubic Dresselhaus SOC in 2DEGs promotes a strong anisotropy of the band spin splitting which in turn leads to a very characteristic frequency dependence of the spin Hall conductivity. We find that the spin Hall conductivity response could be very sensible to sizeable cubic-Dresselhaus coupling strength. This may be of relevance for the optical control of spin currents in 2DEGs with non-negligible cubic-Dresselhaus SOC.

The electronic structure and magnetism of Mn2SnS4 are analysed with full-potential first-principles calculations. In order to understand the possible influence of magnetic structure, we have performed calculations of total energies for both ferromagnetic (FM) and antiferromagnetic (AFM) orderings. Antiferromagnetic ordering is of three types. Our computed results reveal that Mn2SnS4 exhibits an AFM-I type antiferromagnetic ordering. The exchange interaction parameters, which reflects the electrostatic Coulomb repulsion of electrons on neighboring atoms and the Pauli principle, were estimated to be J1 = − 14.1 meV, J2= − 5.3 meV and J3 = − 8.2 meV according to the Heisenberg model. It was shown that all values are negative and J1 has the highest absolute value, demonstrating strong antiferromagnetic pairing dominating between the nearest magnetic Mn ions and weak antiferromagnetic coupling within the next-nearest Mn ions. The position of the sulfur atoms have no impact on the values of the aforementioned energies, which validates that the magnetism in Mn2SnS4 is dominated mainly by direct exchange. The associated energy differences involving spin orderings can be used to evaluate the critical temperature of the compounds Mn2SnS4. Our calculations show that taking into account the spin–orbit coupling has no significant effect on the accuracy of the band gap of Mn2SnS4. The calculated results of equilibrium volume, antiferromagnetic ordering type, local magnetic moment, and band gap are in good agreement with reported experimental results. The relative differences between spin configurations can be used to derive observables such as Curie-Weiss temperature (θ). The Curie-Weiss temperature is calculated using the mean-field approximation. Reasonable agreement with the experiment is found for all properties including the equilibrium volume, local magnetic moment, antiferromagnetic ordering type, band gap, and the Curie-Weiss temperature. [ABSTRACT FROM AUTHOR]

The nitrogen-vacancy (NV) center in diamond is a widely utilized system due to its useful quantum properties. Almost all research focuses on the negative charge state (NV−) and comparatively little is understood about the neutral charge state (NV0). This is surprising as the charge state often fluctuates between NV0 and NV− during measurements. There are potentially under-utilized technical applications that could take advantage of NV0, either by improving the performance of NV0 or utilizing NV− directly. However, the fine structure of NV0 has not been observed. Here, we rectify this lack of knowledge by performing magnetic circular dichroism measurements that quantitatively determine the fine structure of NV0. The observed behavior is accurately described by spin-Hamiltonians in the ground and excited states with the ground state yielding a spin-orbit coupling of λ = 2.24 ± 0.05 GHz and a orbital g-factor of 0.0186 ± 0.0005. The reasons why this fine structure has not been previously measured are discussed and strain-broadening is concluded to be the likely reason.

Converting charge current into spin current is one of the main mechanisms exploited in spintronics. One prominent example is the Edelstein effect, namely, the generation of a magnetization in response to an external electric field, which can be realized in systems with lack of inversion symmetry. If a system has electrons with an orbital angular momentum character, an orbital magnetization can be generated by the applied electric field, giving rise to the so-called orbital Edelstein effect. Oxide heterostructures are the ideal platform for these effects due to the strong spin–orbit coupling and the lack of inversion symmetries. Beyond a gate-tunable spin Edelstein effect, we predict an orbital Edelstein effect an order of magnitude larger then the spin one at the (111) LaAlO3/SrTiO3 interface for very low and high fillings. We model the material as a bilayer of t2g orbitals using a tight-binding approach, whereas transport properties are obtained in the Boltzmann approach. We give an effective model at low filling, which explains the non-trivial behaviour of the Edelstein response, showing that the hybridization between the electronic bands crucially impacts the Edelstein susceptibility.

Using first principle calculations based on the density functional theory (DFT), the structural, elastic, electronic, and thermoelectric properties, and thermodynamic stability of the LiMgZ (Z = P, As, Bi) half-Heusler ternary compounds were studied. The results of structural calculations and elastic constants and investigation of the thermodynamic phase diagram represent stability for these compounds in the half-Heusler cubic structure with F4-3 m symmetry. Studying the electronic structure using generalised gradient approximation (GGA) as well as spin-orbit calculations (SOC) reveal that all three LiMgZ (Z = P, As, Bi) structures are non-magnetic semiconductors with an indirect band gap along Г-X direction with values of 1.63, 1.37 and 0.5 eV, respectively. The electron transport behaviours of these materials at various temperatures show that their dimensionless figure of merit (ZT) at the temperature of 200 K reaches its maximum value of 0.813, 0.81 and 0.78 for LiMgP, LiMgAs and LiMgBi, respectively. [ABSTRACT FROM AUTHOR]

We have studied the spin-orbit coupling via inelastic scattering on the intrasubband spin density excitation. Resonant in elastic scattering was applied to the probe of the anisotropic spin splitting of two dimensional hole systems in p-modulation doped gallium arsenide quantum wells. Intrasubband spin density excitations on a sample was used where evidence of the persistent spin helix was shown by direct spatial mapping. We found approximately equal strengths of Rashba and Dresselhaus spinorbit coupling and anisotropy maximal. The spin splitting for in plane spin was also found maximal and in the perpendicular [110] direction was smaller. The spin splitting of in plane of about 0.18 meV and in the perpendicular in plane direction was found to be smaller than 0.05 meV. We have theoretically studied that only spin flip transitions between the spin orbit split conduction band subbands contributed significantly to the intrasubband spin-density excitation in quasi-backscattering geometry. The obtained results were found in good agreement with previously obtained results. [ABSTRACT FROM AUTHOR]

In this paper, we study Hall effects of the monolayer MoS2 with Rashba and Ising spin-orbit coupling (SOC) under the application of a circularly polarized light. The Chern number and spin textures at high frequency regime are studied based on the Floquet theory. We found that the SOCs induced valley Hall effect. The sign of Chern numbers at high frequency regime can be reversed by engineering interplay between Ising SOC and light intensity. The system undergoes a topological phase transition from valley Hall state to anomalous Hall state. By analyzing the spin texture, we study the origin of the Hall effects. [ABSTRACT FROM AUTHOR]

Several dynamical systems of interest in Celestial Mechanics can be written in the form of a Newton equation with time-dependent damping, linear in the velocities. For instance, the modified Kepler problem, the spin–orbit model and the Lane–Emden equation all belong to such class. In this work, we start an investigation of these models from the point of view of contact geometry. In particular, we focus on the (contact) Hamiltonisation of these models and on the construction of the corresponding geometric integrators. [ABSTRACT FROM AUTHOR]

This paper deals with the rotation and figure evolution of a planet near the 3/2 spin–orbit resonance and the exploration of a new formulation of the creep tide theory (Folonier et al. in Celest Mech Dyn Astron 130:78, 2018). This new formulation is composed by a system of differential equations for the figure and the rotation of the body simultaneously (which is the same system of equations used in Folonier et al. 2018), different from the original one (Ferraz-Mello in Celest Mech Dyn Astron 116:109–140, 2013; Celest Mech Dyn Astron 122:359–389, 2015a. arXiv: 1505.05384) in which rotation and figure were considered separately. The time evolution of the figure of the body is studied for both the 3/2 and 2/1 spin–orbit resonances. Moreover, we provide a method to determine the relaxation factor γ of non-rigid homogeneous bodies whose endpoint of rotational evolution from tidal interactions is the 3/2 spin–orbit resonance, provided that (i) an initially faster rotation is assumed and (ii) no permanent components of the flattenings of the body existed at the time of the capture in the 3/2 spin–orbit resonance. The method is applied to Mercury, since it is currently trapped in a 3/2 spin–orbit resonance with its orbital motion and we obtain 4.8 × 10 - 8 s - 1 ≤ γ ≤ 4.8 × 10 - 9 s - 1 . The equatorial prolateness and polar oblateness coefficients obtained for Mercury's figure with such range of values of γ are the same as the ones given by the Darwin–Kaula model (Matsuyama and Nimmo in J Geophys Res 114, E01010, 2009). However, comparing the values of the flattenings obtained for such range of γ with those obtained from MESSENGER's measurements (Perry et al. in Geophys. Res. Lett. 42, 6951–6958, 2015), we see that the current values for Mercury's equatorial prolateness and polar oblateness are 2–3 orders of magnitude larger than the values given by the tidal theories. [ABSTRACT FROM AUTHOR]

• The bond lengths in case of excited states are close to that of the ground state. • The rotational constants for higher states are nearer their corresponding experimental values. • The energy levels of 4I spin-orbit states of U3+ ion are not affected much in the presence of oxide ion in UO+. The relativistic two-component ab initio calculations have been carried out to calculate the electronic structure and spectroscopic properties of UO+ ion. The State-Averaged Restricted Active Space Self-Consistent Field (SA-RASSCF) calculations have been performed with spin-orbit effects. The ground state along with a manifold of low-lying spin-orbit states below 12 600 cm−1 have been reported and compared with available results from experiment, Ligand Field Theory (LFT) and previous theoretical results. The configurational assignments along with spectroscopic properties at equilibrium bond distances and also the nature of the potential energy curves have been reported. The ground state Ω = 9/2 at R = 1.790 Å is found to be ionic in nature, U3+(5 f 3(4I))O2−(1S), with a vibrational frequency of 962 cm−1. The computed excitation energies compare reasonably well with the available experimental counterpart. [ABSTRACT FROM AUTHOR]

We present here polarization operator of non-relativistic fermions with spin-orbit (SO) Rashba interaction. The spectrum of this fermions is moat type having minimum on a circle. Contrary to Dirac or non-relativistic fermions, Fermi sea here has a geometry of Corbino disk which reflects in a transport properties of excitation's. [ABSTRACT FROM AUTHOR]

Abstract We study the formation of local moments in a metallic host due to a localized spin-orbit (Rashba) interaction. Using the Anderson model we describe the occurrence of magnetic moments through calculation of the magnetic-non-magnetic phase transition within the mean-field scenario. We compare our results with those in the absence of the Rashba interaction. The symmetry and regime of the magnetic phase demonstrates a dependence on the above interaction. The conductance values through the impurities are also exhibited for the above phases. Highlights • The formation of local moments in quantum dots in a metallic host due to Rashba term is studied. • The phase diagram depends on the impurity energy. • The occupation numbers depend on the Rashba interaction. • The magnetization molds the adimensional conductance. [ABSTRACT FROM AUTHOR]

We report first-principles calculations, within density functional theory, on the lead halide compounds PbCl2, PbBr2, and CH3NH3PbBr3−xClx, taking into account spin-orbit coupling. We show that, when the modified Becke-Johnson exchange potential is used with a suitable choice of defining parameters, excellent agreement between calculations and experiment is obtained. The computational model is then used to study the effect of replacing the methylammonium cation in CH3NH3PbI3 and CH3NH3PbBr3 with either N2H5+or N2H3+, which have slightly smaller ionic radii than methylammonium. We predict that a considerable downshift in the values of the band gaps occurs with this replacement. The resulting compounds would extend optical absorption down to the near-infrared region, creating excellent light harvesters for solar cells.

This study reports the spin–orbit effects on the aromaticity of the N 5 −, P 5 −, As 5 −, Sb 5 −, Bi 5 −, and Mc 5 − anionic clusters via the magnetically induced current‐density method. All‐electron density functional theory (DFT) calculations were carried out using the four‐component Dirac‐Coulomb (DC) hamiltonian, including scalar and spin–orbit relativistic effects. The magnetic index of aromaticity was calculated by numerical integration over the current flow between two atoms in the pentagonal ring. These values were compared to the spin‐free values (spin–orbit coupling switched off), in order to assess the spin–orbit effect on aromaticity. It was found that in the heavy anions, Bi 5 − and Mc 5 −, there is a significant influence of the spin–orbit coupling. © 2018 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Abstract: A spin‐forbidden chemical reaction involves a change in the total electronic spin state from reactants to products. The mechanistic study is challenging because such a reaction does not occur on a single diabatic potential energy surface (PES), but rather on two (or multiple) spin diabatic PESs. One possible approach is to calculate the so‐called “minimum energy crossing point” (MECP) between the diabatic PESs, which however is not a stationary point. Inclusion of spin–orbit coupling between spin states (SOC approach) allows the reaction to occur on a single adiabatic PES, in which a transition state (TS SOC) as well as activation free energy can be calculated. This Concept article summarizes a previously published application in which, for the first time, the SOC effects, using spin–orbit ZORA Hamiltonian within density functional theory (DFT) framework, are included and account for the mechanism of a spin‐forbidden reaction in gold chemistry. The merits of the MECP and TS SOC approaches and the accuracy of the results are compared, considering both our recent calculations on molecular oxygen addition to gold(I)‐hydride complexes and new calculations for the prototype spin‐forbidden N2O and N2Se dissociation reactions. [ABSTRACT FROM AUTHOR]

Abstract: The role of the spin‐orbit coupling in Au38(SR)24, as a representative case for a superatomic molecules is studied to offer a complete view of the relativistic effect in heavy elements clusters. Its Au 23 9 + core can be described in as an analog to a diatomic molecule, such as F2, allowing the electronic structure to be depicted in terms of the D∞h point group. First, we showed the electronic structure under the spin‐orbit framework using total angular momentum representations (j = ℓ ± s; spinors), which allows us to characterize the expected splitting of certain levels derived from the cluster core. Accordingly, the optical properties are evaluated under spin‐orbit coupling regime, revealing differences in the low‐energy region of the absorption spectrum. Lastly, the variation of electron affinity (EA) and ionization potential (IP) properties is evaluated. This reveals characteristic consequences of the inclusion of spin‐orbit coupling in Au38(SR)24, as a bridge to larger thiolate‐protected gold clusters. [ABSTRACT FROM AUTHOR]

We study the modification of the electronic structure in the strong spin–orbit coupled Sr _2 IrO _4 by epitaxial strain using density-functional methods. Structural optimization shows that strain changes the internal structural parameters such as the Ir–O–Ir bond angle, which has an important effect on the band structure. An interesting prediction is the Γ− X crossover of the valence band maximum with strain, while the conduction minimum at M remains unchanged. This in turn suggests strong strain dependence of the transport properties for the hole-doped system, but not when the system is electron doped. Taking the measured value of the Γ− X separation for the unstrained case, we predict the Γ− X crossover of the valence band maximum to occur for the tensile epitaxial strain e _xx ≈ 3%. A minimal tight-binding model within the J _eff = 1/2 subspace is developed to describe the main features of the band structure. The optical absorption spectra under epitaxial strain are computed using density-functional theory, which explains the observed anisotropy in the optical spectra with the polarization of the incident light. We show that the optical transitions between the Ir ( d ) states, which are dipole forbidden, can be explained in terms of the admixture of Ir ( p ) orbitals with the Ir ( d ) bands.

The O h -[Au 6 ] 2+ cluster exhibits an open-shell 1 s 2 1 p 2 which trend to a more stable D 2 h isomer in 31.5 kcal/mol, as observed in the experimental [Au 6 {P(C 6 H 4 Me-o)pH 2 } 6 ] cluster. By taking into account the spin-orbit coupling (SOC) in O h -[Au 6 ] 2+ , a resulting 1 s 1/2 2 1 p 1/2 2 closed-shell superatomic configuration is obtained stabilizing such structure by about 14.7 kcal/mol, decreasing the isomerization barrier. Thus, the spin-orbit term favors the O h ↔ D 2 h conformation rearrangement depicting a decrease in the calculated energy difference between both conformations, an interesting consequence which is not obtained in the hypothetical lighter counterparts. [ABSTRACT FROM AUTHOR]

We present in this work density functional theory calculations of the structural and electronic properties of (PbS) nanoparticles with n = 4-32. Particular care has been taken on the correct description of their electronic structure by using a hybrid functional including the spin-orbit coupling effects. We demonstrate that the bonding in PbS nanoparticles is quite different from bulk PbS as the six Pb-S bonds around a single Pb atom are found to have a different character while in bulk PbS all Pb-S distances are equivalent. We also relate the geometric structure to the evolution of the HOMO-LUMO gaps and show how the computed electronic properties strongly depend on the functional used. Finally, based on an extrapolation of our results, we predict that to obtain the onset of absorption in the infrared region of the spectrum a cubic nanoparticle of ~1.96 nm side length is needed, a result that is in agreement with existing experimental information. [ABSTRACT FROM AUTHOR]

We report about the spin-orbit effects on the aromaticity of the B 4 2 - , Al 4 2 - , Ga 4 2 - , In 4 2 - and Tl 4 2 - clusters via the magnetically-induced current density method. All-electron density functional theory (DFT) calculations were carried out using the four-component Dirac-Coulomb (DC) Hamiltonian, including scalar and spin-orbit relativistic effects. The relativistic values for ring current strengths were obtained by numerical integration over the current flow. These values were compared to the scalar relativistic and non-relativistic values, in order to assess the corresponding contributions to aromaticity. It was found that in the heavy cluster, Tl 4 2 - , there is a significant influence of both scalar and spin-orbit relativistic effects. [ABSTRACT FROM AUTHOR]

We investigate the spin-resolved transport in a two-terminal zigzag graphene nanoribbon device with two independent gate induced Rashba spin-orbit coupling regions and in the presence of strain. By employing a recursive Green's function technique to the tight-binding model for the graphene nanoribbon, we calculate the spin-resolved conductance of the system. We show that by switching the sign of one of the gates it is possible to select which spin component will be transmitted. Moreover, our results show that an uniaxial strain applied to the nanoribbon plays a significant role in the transport, providing and additional manner to control the spin-polarized conductance. This makes the present system a potential candidate for future implementations of spin-based mechanical strain sensors. [ABSTRACT FROM AUTHOR]

Nonreciprocity in optical fibers are opening new avenues for fields such as quantum computing and quantum photonics. In this study we explore the chiral properties of the radiation modes of optical fibers and show that whispering gallery mode resonances, as part of radiation modes, carry specific transverse spin angular momenta. The transverse spin angular momentum is different for forward and backward propagating radiation modes, hence indicating spin–momentum locking. As a result of spin–momentum locking, a nonreciprocity in the emission coupling of an atomic transition with a specific spin into the forward and backward propagating modes is observed. Modeling an atomic transition by a classical dipole that rotates clockwise or anticlockwise, we optimize the position of the dipole within the optical fiber to achieve maximum nonreciprocity between the coupling of the dipole emission into the forward or backward propagating mode. We find near-perfect nonreciprocity in both radiation and guided modes and further outline the fiber diameter and dipole position to achieve this state. This study not only shows the rich physics of fiber radiation modes within the context of light–matter interaction but also complements previous studies of nonreciprocity in subwavelength waveguides. • Explores the nonreciprocity in optical fiber radiation modes. • The family of whispering gallery modes have specific spin angular momenta. • Experimental set up for perfect nonreciprocity in both radiation and guided modes. • First proposed method to select specific radiation modes. [ABSTRACT FROM AUTHOR]

The aim of this paper is to build and validate some explicit high-order schemes, both in space and time, for simulating the dynamics of systems of nonlinear Schrödinger/Gross–Pitaevskii equations. The method is based on the combination of high-order IMplicit–EXplicit (IMEX) schemes in time and Fourier pseudo-spectral approximations in space. The resulting IMEXSP schemes are highly accurate, efficient and easy to implement. They are also robust when used in conjunction with an adaptive time stepping strategy and appear as an interesting alternative to time-splitting pseudo-spectral (TSSP) schemes. Finally, a complete numerical study is developed to investigate the properties of the IMEXSP schemes, in comparison with TSSP schemes, for one- and two-components systems of Gross–Pitaevskii equations. [ABSTRACT FROM AUTHOR]

In developing physical theories, analogical reasoning has been found to be very powerful, as attested by a number of important historical examples. An analogy between two apparently different phenomena, once established, allows one to transfer information and bring new concepts from one phenomenon to the other. Here, we discuss an important analogy between two widely different physical problems, namely, the Jahn-Teller distortion in molecular physics and the Rashba spin splitting in condensed matter physics. By exploring their conceptual and mathematical features and by searching for the counterparts between them, we examine the orbital texture in Jahn-Teller systems, as the counterpart of the spin texture of the Rashba physics, and put forward a possible way of experimentally detecting the orbital texture. Finally, we discuss the analogy by comparing the coexistence of linear Rashba + Dresselhaus effects and Jahn-Teller problems for specific symmetries, which allow for nontrivial spin and orbital textures, respectively. [ABSTRACT FROM AUTHOR]

Due to the recent experimental progress, tunable spin-orbit (SO) interactions represent ideal candidates for the control of polarization and dynamical spin properties in both quantum wells and cold atomic systems. A detailed understanding of spin properties in SO-coupled systems is thus a compelling prerequisite for possible novel applications or improvements in the context of spintronics and quantum computers. Here, we analyze the case of equal Rashba and Dresselhaus couplings in both homogeneous and laterally confined two-dimensional systems. Starting from the single-particle picture and subsequently introducing two-body interactions we observe that periodic spin fluctuations can be induced and maintained in the system. Through an analytical derivation, we show that the two-body interaction does not involve decoherence effects in the bosonic dimer, and, in the repulsive homogeneous Fermi gas, it may be even exploited in combination with the SO coupling to induce and tune standing currents. By further studying the effects of a harmonic lateral confinement-a particularly interesting case for Bose condensates-we evidence the possible appearance of nontrivial spin textures, whereas the further application of a small Zeeman-type interaction can be exploited to fine-tune the system's polarizability. [ABSTRACT FROM AUTHOR]

Because it has been shown that the silicon trimer has a strong multi-reference character, accurate multi-reference configuration interaction calculations are performed to elucidate its electronic manifold. Emphasis is given to the long-range part of the potential, aiming to understand the atom–diatom collision's dynamical aspects and to describe the conical intersections and important saddle points along the reaction path. An analysis of the main features of the potential energy surface is performed for benchmarking, and highly accurate values for structures, vibrational constants and energy gaps are reported, as well as a previously unpublished spin–orbit coupling magnitude. The results predict that intersystem crossings will play an important role in dynamical simulations, especially in triplet-state quenching, making the problem of constructing a precise potential energy surface more complicated and multi-sheet dependent. The ground state is predicted to be the singlet, but because the singlet–triplet gap is rather small (2.448 kJ/mol), both of these states are expected to be populated at room temperature. [ABSTRACT FROM AUTHOR]

Optical, magnetic properties and the low-energy region of the electronic spectra in the Nd 3 + and U 3 + fluoride complexes embedded in CaF 2 have been analyzed. The effect of the local charge compensation by interstitial F - could be evaluated via the crystal field (CF) distortion with respect to the ideal octahedral environment. All the result were obtained with the help of ab initio wave function calculations including spin–orbit coupling (SO) via the MRCI state interaction of scalar relativistic CAS wave functions. The level of theory employed in this work shows a good correlation between the experimental and calculated spectroscopic properties allowing not only the correct determination of the f → f transitions, but also the f → d transitions in the absorption spectra. An analysis of the ground states and the magnetic behavior is performed using crystal-field (CF) models with parameters extracted from the ab initio calculations. The calculated g -factors are in concordance with the experimental data. [ABSTRACT FROM AUTHOR]

We report first-principles calculations, within density functional theory, on the lead halide compounds PbCl2, PbBr2, and CH3NH3PbBr3-xClx, taking into account spin-orbit coupling. We show that, when the modified Becke-Johnson exchange potential is used with a suitable choice of defining parameters, excellent agreement between calculations and experiment is obtained. The computational model is then used to study the e ect of replacing the methylammonium cation in CH3NH3PbI3 and CH3NH3PbBr3 with either N2H+ 5 or N2H+ 3 , which have slightly smaller ionic radii than methylammonium. We predict that a considerable downshift in the values of the band gaps occurs with this replacement. The resulting compounds would extend optical absorption down to the near-infrared region, creating excellent light harvesters for solar cells. [ABSTRACT FROM AUTHOR]

In this work, we have investigated the structural, electronic and optical properties of zinc-blende (ZB) GaAs 1− x Bi x ternary alloys at normal and under hydrostatic pressure. Firstly, we have performed the calculation of the structural and electronic properties of binary compounds GaAs and GaBi and for GaAs 1− x Bi x ternary alloy at different compositions x =0.0625, 0.125, 0.25, 0.5 and 0.75. It is observed that lattice parameter increases with increasing Bi content; however the direct band gap E g Γ - Γ of GaAsBi decreases non-linearly. We have studied the variation of the spin–orbit splitting energy Δ so with respect of Bi compositions. Our study shows that the Δ so exceeds the energy gap E g for bismuth fractions greater than 15%. We have also studied the effect of hydrostatic pressure on the structural, electronic and optical properties of the GaAs 0.9375 Bi 0.0625 , GaAs 0.875 Bi 0.125 and GaAs 0.75 Bi 0.25 . We found that the application of hydrostatic pressure leads to variation of the electronic and optical properties of these materials. [ABSTRACT FROM AUTHOR]

We review measurements of angle and time resolved photoelectron spectroscopy on the surface states of the Bi(1 1 1) surface. The work covers several aspects of these surface states, discussing the topological properties, the strong anisotropy of the spin–orbit splitting and the dynamical relaxation of photoexcited electrons. Since time resolved experiments disentagle interaction processes in real time, the reported data offer a novel perspective on the motion of charge carriers in surface states and will serve as an unuseful reference for other systems with strong spin–orbit coupling. [ABSTRACT FROM AUTHOR]

We give a unitary description of T-odd effects in various sectors of atomic, nuclear and particle physics, like elastic scattering, deep inelastic processes and weak decays. This we get thanks to a particular transformation, which suggests a simple and unambiguous procedure for defining the two typical T-odd observables, the azimuthal asymmetry and the normal polarization. This approach allows to revise the two observables quite naturally in various situations, mainly in deep inelastic processes and in weak decays. In the latter case, useful suggestions for phenomenological analyses and an interesting result for normal and transverse polarization are derived. [ABSTRACT FROM AUTHOR]

Irreducible tensor operators formulism has been employed to derive basis set charge densities from the expressions of t 2 g and e g eigenstates. The resulting basis set has been utilized to generate and visualized charge densities of pure and hybrid charge densities of single d electron and many-electron systems of transition-metal compounds. The role-plays by spin–orbit coupling contribution in mixing the densities have been demonstrated. The ground states of pentagonal bipyramidal, square planar, and trigonal bipyramidal complexes are due to spin–orbit coupling. The resulting charge densities are in full agreement with previous works in the literature. [ABSTRACT FROM AUTHOR]