Laser-controlled local magnetic field with semiconductor quantum rings

Pershin, Yuriy V.; Piermarocchi, Carlo

doi:10.1103/physrevb.72.245331

Cited by 62 publications

(33 citation statements)

References 28 publications

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“…Such currents have been numerically observed in atoms and ions, 18 in oriented linear molecules, 19,20 and in oriented aromatic molecules. [21][22][23][24][25] Electric ring currents and associated magnetic fields can also be generated in two-dimensional nanosized quantum rings by means of picosecond laser pulses, e.g., by two shaped timedelayed laser pulses with perpendicular linear polarizations, 26 by circularly polarized laser pulses, 27 or by optimized laser pulses designed through optimal-control theory. 28 Electron circulation in chiral aromatic molecules can be manipulated by means of linearly polarized laser pulses, 29,30 but the direction of the electric ring currents alternates periodically after the end of laser pulses due to the nondegeneracy of the excited states.…”

Section: Introductionmentioning

confidence: 99%

Nonadiabatic orientation, toroidal current, and induced magnetic field in BeO molecules

Barth

Serrano‐Andrés

Seideman

2008

The Journal of Chemical Physics

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It is predicted that oriented BeO molecules would give rise to unprecedentedly strong, unidirectional electric ring current and an associated magnetic field upon excitation by a right or left circularly polarized laser pulse into the first excited degenerate singlet state. The strong toroidal electric ring current of this state is dominated by the ring current of the 1 Ϯ orbital about the molecular axis. Our predictions are based on the analysis of the orbital composition of the states involved and are substantiated by high level electronic structure calculations and wavepacket simulations of the laser-driven orientation and excitation dynamics.

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Section: Introductionmentioning

confidence: 99%

Nonadiabatic orientation, toroidal current, and induced magnetic field in BeO molecules

Barth

Serrano‐Andrés

Seideman

2008

The Journal of Chemical Physics

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“…It is interesting to note that the photon field couples directly to the spin via Eqs. (8), (9) and (6). For reasons of comparison and to determine the photocurrents, we also consider results without photons in [32,33,54] by letting the photon cavity be much larger than the quantum ring (this assumption is used in the derivation of the vector potential, Eq.…”

Section: Central System Hamiltonianmentioning

confidence: 99%

“…Circularly polarized light emission [5] and absorption [6] has been studied for quantum rings. Moreover, circularly polarized light has been used to generate persistent charge currents in quantum wells [7] and quantum rings [8,9,10,11]. The basic principle behind this is a change of the orbital angular momentum of the electrons in the quantum ring by the absorption or emission of a photon leading to the circular charge transport.…”

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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“…There is for example a substantial range of literature available on Aharonov-Bohm and persistent current effects on quantum ring structures. For more recent experimental and theoretical results please refer to [6][7][8][9][10][11]. Toroidal structures allow for electron motion around the major radius R (azimuthal or dipole mode) and the minor radius a (solenoidal modes) of a circularly symmetric torus, which is subject to specific boundary conditions which are different from those for flat two-dimensional rings.…”

mentioning

confidence: 99%

Dipole and solenoidal magnetic moments of electronic surface currents on toroidal nanostructures

Encinosa

Jack

2007

J Computer-Aided Mater Des

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The time-dependent Schrödinger equation is developed for a spinless electron which is confined to move on a toroidal surface and curvature effects are taken into account. The electron motion is driven by linearly or circularly polarized microwaves including an interference field. To calculate the magnetic moments which are induced by the electronic surface currents on the torus an eight-state basis set is used. The system is driven at a resonance frequency to allow for transitions between states with opposite θ -parity. Optical transitions into modes of excitation can be observed that correspond to a magnetic dipole term parallel to the toroidal central symmetry axis as well as additional components in radial and azimuthal direction (solenoidal modes). Size and relative magnitude of the different components can be steered by adjusting magnitude, polarization, and phase information of the microwave field. Substantial enhancements of the solenoidal magnetic modes versus the dipole mode can be observed when adding a sufficiently strong static magnetic field parallel to the symmetry axis.

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Laser-controlled local magnetic field with semiconductor quantum rings

Cited by 62 publications

References 28 publications

Nonadiabatic orientation, toroidal current, and induced magnetic field in BeO molecules

Nonadiabatic orientation, toroidal current, and induced magnetic field in BeO molecules

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

Dipole and solenoidal magnetic moments of electronic surface currents on toroidal nanostructures

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