100 research outputs found
Spin noise in quantum dot ensembles
We study theoretically spin fluctuations of resident electrons or holes in
singly charged quantum dots. The effects of external magnetic field and
effective fields caused by the interaction of electron and nuclei spins are
analyzed. The fluctuations of spin Faraday, Kerr and ellipticity signals
revealing the spin noise of resident charge carriers are calculated for the
continuous wave probing at the singlet trion resonance.Comment: 8 pages, 4 figure
Electron Spin Dynamics in Impure Quantum Wells for Arbitrary Spin-Orbit Coupling
Strong interest has arisen recently on low-dimensional systems with strong
spin-orbit interaction due to their peculiar properties of interest for some
spintronic applications. Here, the time evolution of the electron spin
polarization of a disordered two-dimensional electron gas is calculated exactly
within the Boltzmann formalism for arbitrary couplings to a Rashba spin-orbit
field. The classical Dyakonov-Perel mechanism of spin relaxation is shown to
fail for sufficiently strong Rashba fields, in which case new regimes of spin
decay are identified. These results suggest that spin manipulation can be
greatly improved in strong spin-orbit interaction materials.Comment: 5 pages, 2 figures -revised versio
Non-Markovian spin relaxation in two-dimensional electron gas
We analyze by Monte-Carlo simulations and analytically spin dynamics of
two-dimensional electron gas (2DEG) interacting with short-range scatterers in
nonquantizing magnetic fields. It is shown that the spin dynamics is
non-Markovian with the exponential spin relaxation followed by the oscillating
tail due to the electrons residing on the closed trajectories. The tail relaxes
on a long time scale due to an additional smooth random potential and inelastic
processes. The developed analytical theory and Monte-Carlo simulations are in
the quantitative agreement with each other.Comment: 6 pages, 3 figure
Non-exponential spin relaxation in magnetic field in quantum wells with random spin-orbit coupling
We investigate the spin dynamics of electrons in quantum wells where the
Rashba type of spin-orbit coupling is present in the form of random nanosize
domains. We study the effect of magnetic field on the spin relaxation in these
systems and show that the spatial randomness of spin-orbit coupling limits the
minimum relaxation rate and leads to a Gaussian time-decay of spin polarization
due to memory effects. In this case the relaxation becomes faster with increase
of the magnetic field in contrast to the well known magnetic field suppression
of spin relaxation.Comment: published version, minor change
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