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[IEEE 2018 IEEE 38th International Conference on Electronics and Nanotechnology (ELNANO) - Kiev (2018.4.24-2018.4.26)] 2018 IEEE 38th International Conference on Electronics and Nanotechnology (ELNANO) - Influence of Spin-Orbit Interaction on the Magneto-Optical Spectra of InSb Quantum Rings
摘要： The theoretical calculations of dependences of energy levels and absorption spectra of electrons in the quantum ring by a quasi-parabolic shape on the applied external magnetic field were carried out. The influence of spin-orbit interaction was taken into account in these calculations. Spin-orbit interaction leads to appearance of change in the dependence of absorption frequency of quantum rings on applied magnetic field.
关键词： spin-orbit interaction,absorption spectrum,quantum ring
更新于2025-09-23 15:22:29
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Influence of electric field on direct and indirect exciton in a concentrically coupled quantum ring heterostructure embedded in SiO2 matrix
摘要： Excitonic states of Concentric Double Quantum Ring (CDQR) heterostructures embedded in SiO2 matrix under the influence of electric field has been calculated theoretically using variational technique. CDQR has been confined in a quantum well of suitable width which serve as the height of the quantum ring along which the electric field is applied. Central barrier width, outer ring width and carrier location has been tuned to understand the localization of both direct and indirect excitons. Effect of ring dimension and electric field on the energy states of Inner Ring Exciton (IRE) and Outer Ring Exciton (ORE) has been determined. Tilting of conduction and valence bands due to the application of electric field invokes a triangular confinement to the carriers and the same has been discussed. Diamagnetic susceptibility which is merely an indicator of electron hole separation and intersubband transition energy has also been calculated for both symmetric and asymmetric quantum ring. Height of the QR has also been changed to study its effect on the diamagnetic susceptibility of an exciton.
关键词： Diamagnetic Susceptibility,Quantum Ring,Exciton,Binding energy,Electric Field
更新于2025-09-12 10:27:22
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Ultrafast mixing of radial and spin states driven by transient magnetic field in concentric double quantum ring in presence of Dresselhaus spin-orbit interaction
摘要： We consider the single- and two-electron systems confined in concentric double quantum ring (DQR) nanostructure which interacts with transient perpendicular magnetic field oscillating with THz frequency. For this purpose we find the solutions of time-dependent Schr?dinger equation utilizing Configuration Interaction method. We found that the transient magnetic field mixes the radial states, what trigger off the charge density oscillations in this direction, and these may be accompanied by spin oscillations, provided that a spin-orbit interaction (SOI) is involved. The pattern of density oscillations is more regular than those obtained for single- and two-electron spins what results from less complicated excitation energy spectra if SOI is not present in the system. The latter can be made more regular, i.e. the fluctuations of frequency and amplitude of spin oscillations shall be smaller, provided that the sign of the magnetic field at the begining of time evolution is chosen apropriately since not all energy levels corresponding to bJz = bLz (cid:0) bSz eigenstates have mirror symmetry in relation to B ! (cid:0)B transformation. Our outcomes indicate, that the combined effect of a few-picosecond-long magnetic pulse and SOI on electron spin in DQR would enable one to perform transition between spin-up and spin-down states within 2 ps.
关键词： spin-orbit interaction,quantum ring,magnetic pulse
更新于2025-09-10 09:29:36
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Oscillatory behaviour in the energy and nonlinear optical rectification spectra of elliptic quantum rings under electric field: influence of impurity and eccentricity
摘要： We have theoretically investigated the electronic properties and nonlinear optical rectification spectra of GaAs/AlGaAs anisotropic quantum ring, modelled by an outer ellipsis and an inner circle, in connection to the presence of a donor off-centre impurity, structural distortions and in-plane electric field. The one-electron energy spectrum and wave functions are found using the adiabatic approximation and the finite element method within the effective-mass model. The energy spectrum of the ring reveals an anomalous oscillatory behaviour in the region of relatively small values of the electric field (< 12 kV/cm) followed by linear Stark effect at higher field values. We showed that this unusual behaviour is strongly affected by the ratio of the outer/inner ring radii, the displacement of the inner circle (eccentricity) along the x or y axis and the impurity presence. The related nonlinear optical rectification spectra present maxima whose positions mirror this oscillatory behaviour and consequently can be used as an excellent tool to distinguish the presence of an impurity or the direction of the eccentricity.
关键词： nonlinear optical rectification,eccentricity,Quantum ring,donor impurity,electric field
更新于2025-09-09 09:28:46