Nonresonant circularly polarized electromagnetic radiation can exert torques on magnetizations by the inverse Faraday effect (IFE). Here, we discuss the enhancement of IFE by spin-orbit interactions. We illustrate the principle by studying a simple generic model system, i.e., the quasi-one-dimensional ring in the presence of linear/cubic Rashba and Dresselhaus interactions. We combine the classical IFE in electron plasmas that is known to cause persistent currents in the plane perpendicular to the direction of the propagation of light with the concept of current and spin-orbit-induced spin transfer torques. We calculate light-induced spin polarization that in ferromagnets might give rise to magnetization switching.

We study the transport of electrons through a single-mode quantum ring with electric-field induced Rashba spin-orbit interaction that is subject to an in-plane magnetic field and weakly coupled to electron reservoirs. Modeling a ring array by ensemble averaging over a Gaussian distribution of energy-level positions, we predict slow conductance oscillations as a function of the Rashba interaction and electron density due to spin-orbit interaction induced beating of the spacings between the levels crossed by the Fermi energy. The Aharonov-Casher (AC) effect 1 is an analog of the Aharonov-Bohm (AB) effect but is caused by the spin-orbit interaction (SOI) rather than an external magnetic field. Originally, Aharonov and Casher predicted in 1984 that a spin accumulates a phase when the electric charge is circling in an external electric field.1 This situation is similar to a single-mode ballistic ring with Rashba spin-orbit interaction. Quantum rings in high-mobility semiconductor material have therefore attracted extensive attention, both experimentally and theoretically, as model devices to investigate fundamental quantum-mechanical phenomena.In the AC effect, the electrons injected into a quantum ring with SOI acquire spin phases when traversing the two arms due to precession in the effective spin-orbit magnetic field. Interference of the spinor wave functions at the exit point of the ring then leads to an oscillatory conductance as a function of the spin-orbit coupling constant that in Rashba systems can be tuned by an external gate voltage. König et al.2 reported the first experimental evidence of the AC effect in a single HgTe ring by measuring the phase shift of the AB-type magnetoconductance oscillations caused by tuning the Rashba SO strength. Since several sub-bands in the ring were occupied, they supported their experiments by multimode transport calculations. This study focused on the symmetry points, at which the Rashba SOI is small, and high values of the applied magnetic field.2 Experiments on an array of rings 4 agreed well with the theory provided for a single-mode quantum ring symmetrically and strongly coupled to the leads.3 More recently, the zero magnetic-field conductance as a function of gate field has been interpreted in terms of the modulation of (electron-density-independent) Altshuler-Aronov-Spivak (AAS) oscillations by the SOI, 5 emphasizing the importance of statistical averaging by the ring arrays.In reality, however, the situation is not as simple as it appears. The assumed ideal link of the ring to the leads is equivalent to the strong-coupling limit in terms of a connectivity parameter. 6 The implied absence of backscattering is at odds with the interpretation of the observed oscillations in terms of AAS oscillations due to coherent backscattering. 5,7Reference 8 addresses the effects of scattering at the contacts of a single-mode Rashba ring to the reservoirs, interpolating between the fully open and isolated ring regimes. However, the experiments 4,5 were not carried out on single ri...

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We present numerical calculations of the impact of charge carriers-carriers interactions on the dynamical properties of quasiparticles such as renormalized velocity and quasiparticle inelastic scattering lifetime in a gapped graphene sheet. Our formalism is based on the many-body G0Wapproximation for the self-energy. We present results for the many-body renormalized velocity suppression and the renormalization constant over a broad range of energy gap values. We find that the renormalized velocity is almost independence of the carrier densities at large density regime. We also show that the quasiparticle inelastic scattering lifetime decreases by increasing the gap value. Finally, we present results for the mean free path of charge carriers suppression over the energy gap values.

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