Electromagnetic pulse-driven spin-dependent currents in semiconductor quantum rings

Zhu, Zhen-Gang; Berakdar, J.

doi:10.1088/0953-8984/21/14/145801

Cited by 10 publications

(9 citation statements)

References 68 publications

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“…The use of the picture of a current loop to relate the current with the magnetization is well justified here because the rings are quite large. Equations (12) indicates that the inter-band coherence is the source for the linear response of the system; then, within linear response the magnetization is fully determined by the inter-band coherence. We here have found a significant difference with the model of a plane wave coupled to a bulk semiconductor, where the quantity that relates to the inter-band coherence is actually the polarization of the system.…”

Section: Orbital Angular Momentummentioning

confidence: 99%

“…Another route to access the spin dynamics is to utilize the magnetic field generated by a charge current [5][6][7][8] which can be triggered in the sample by light irradiation ( [9] and references therein). To achieve temporal and local control of the photo-generated current (and hence the magnetic field) one may exploit the conduction intra-band dynamics initiated by asymmetric electromagnetic pulses in semiconductor-based nanorings that are positioned on a scanning tip [10][11][12][13]. Such rings are with the appropriate parameters ready available [14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

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Electric currents induced by twisted light in Quantum Rings

Quinteiro

Berakdar

2009

Opt. Express

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We theoretically investigate the generation of electric currents in quantum rings resulting from the optical excitation with twisted light. Our model describes the kinetics of electrons in a two-band model of a semiconductor-based mesoscopic quantum ring coupled to light having orbital angular momentum (twisted light). We find the analytical solution, which exhibits a "circular" photon-drag effect and an induced magnetization, suggesting that this system is the circular analog of that of a bulk semiconductor excited by plane waves. For realistic values of the electric field and material parameters, the computed electric current can be as large as microA; from an applied perspective, this opens new possibilities to the optical control of the magnetization in semiconductors.

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Section: Orbital Angular Momentummentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Electric currents induced by twisted light in Quantum Rings

Quinteiro

Berakdar

2009

Opt. Express

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“…3.2 Two pulses case The charge current and the spin current are calculated [15] using the velocity operator…”

Section: Time-dependent Wave Functionsmentioning

confidence: 99%

Photoinduced nonequilibrium spin, charge polarizations and spin‐dependent current in quantum rings

Zhu

Berakdar

2010

Physica Status Solidi (b)

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We investigate the spin-dependent dynamical response of a semiconductor quantum ring with a spin orbit interaction upon the application of a single and two linearly polarized, picosecond, asymmetric electromagnetic pulses in the presence of a static magnetic flux. We find that the pulse-generated electric dipole moment is spin dependent. It is also shown that the spin orbit interaction induces an extra SU(2) effective flux in addition to the static external magnetic flux which is reflected in an additional periodicity of the spin-dependent dipole moment. Furthermore, the pulses may induce a net dynamical charge currents and dynamical spin currents when the clockwise and anti-clockwise symmetry of the carrier is broken upon the pulse application.

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“…While the magnetic flux through the ring causes only equilibrium persistent charge currents [24,25], SOI can also induce equilibrium persistent spin currents [26,27]. Dynamical spin currents can be obtained by two asymmetric electromagnetic pulses [28]. Optical control of the spin current can be achieved by a non-adiabatic, twocomponent laser pulse [29].…”

Section: Introductionmentioning

confidence: 99%

Impact of a circularly polarized cavity photon field on the charge and spin flow through an Aharonov–Casher ring

Arnold

Tang

Manolescu

et al. 2014

Physica E: Low-dimensional Systems and Nanostructures

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We explore the influence of a circularly polarized cavity photon field on the transport properties of a finite-width ring, in which the electrons are subject to spin-orbit and Coulomb interaction. The quantum ring is embedded in an electromagnetic cavity and described by "exact" numerical diagonalization. We study the case that the cavity photon field is circularly polarized and compare it to the linearly polarized case. The quantum device is moreover coupled to external, electrically biased leads. The time propagation in the transient regime is described by a non-Markovian generalized master equation. We find that the spin polarization and spin photocurrents of the quantum ring are largest for circularly polarized photon field and destructive Aharonov-Casher (AC) phase interference. The charge current suppression dip due to the destructive AC phase becomes threefold under the circularly polarized photon field as the interaction of the electrons' angular momentum and spin angular momentum of light causes many-body level splitting leading to three many-body level crossing locations instead of one. The circular charge current inside the ring, which is induced by the circularly polarized photon field, is found to be suppressed in a much wider range around the destructive AC phase than the lead-device-lead charge current. The charge current can be directed through one of the two ring arms with the help of the circularly polarized photon field, but is superimposed by vortices of smaller scale. Unlike the charge photocurrent, the flow direction of the spin photocurrent is found to be independent of the handedness of the circularly polarized photon field.

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Electromagnetic pulse-driven spin-dependent currents in semiconductor quantum rings

Cited by 10 publications

References 68 publications

Electric currents induced by twisted light in Quantum Rings

Electric currents induced by twisted light in Quantum Rings

Photoinduced nonequilibrium spin, charge polarizations and spin‐dependent current in quantum rings

Impact of a circularly polarized cavity photon field on the charge and spin flow through an Aharonov–Casher ring

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