65,325 research outputs found
Analyticity of the Susceptibility Function for Unimodal Markovian Maps of the Interval
In a previous note [Ru] the susceptibility function was analyzed for some
examples of maps of the interval. The purpose of the present note is to give a
concise treatment of the general unimodal Markovian case (assuming real
analytic). We hope that it will similarly be possible to analyze maps
satisfying the Collet-Eckmann condition. Eventually, as explained in [Ru],
application of a theorem of Whitney [Wh] should prove differentiability of the
map restricted to a suitable set.Comment: 8 page
NMR Probing Spin Excitations in the Ring-Like Structure of a Two-Subband System
Resistively detected nuclear magnetic resonance (NMR) is observed inside the
ring-like structure, with a quantized Hall conductance of 6e^2/h, in the phase
diagram of a two subband electron system. The NMR signal persists up to 400 mK
and is absent in other states with the same quantized Hall conductance. The
nuclear spin-lattice relaxation time, T1, is found to decrease rapidly towards
the ring center. These observations are consistent with the assertion of the
ring-like region being a ferromagnetic state that is accompanied by collective
spin excitations.Comment: 4 pages, 4 figure
Comment on "Photon energy and carrier density dependence of spin dynamics in bulk CdTe crystal at room temperature"
We comment on the conclusion by Ma et al. [Appl. Phys. Lett. {\bf 94}, 241112
(2009)] that the Elliott-Yafet mechanism is more important than the
D'yakonov-Perel' mechanism at high carrier density in intrinsic bulk CdTe at
room temperature. We point out that the spin relaxation is solely from the
D'yakonov-Perel' mechanism. The observed peak in the density dependence of spin
relaxation time is exactly what we predicted in a recent work [Phys. Rev. B
{\bf 79}, 125206 (2009)].Comment: 2 page
Intense terahertz laser fields on a quantum dot with Rashba spin-orbit coupling
We investigate the effects of the intense terahertz laser field and the
spin-orbit coupling on single electron spin in a quantum dot. The laser field
and the spin-orbit coupling can strongly affect the electron density of states
and can excite a magnetic moment.
The direction of the magnetic moment depends on the symmetries of the system,
and its amplitude can be tuned by the strength and frequency of the laser field
as well as the spin-orbit coupling.Comment: 5 pages, 4 figures, to be published in J. Appl. Phy
Fabrication and Characterization of Electrostatic Quantum Dots in a Si/SiGe 2D Electron Gas, Including an Integrated Read-out Channel
A new fabrication technique is used to produce quantum dots with read-out
channels in silicon/silicon-germanium two-dimensional electron gases. The
technique utilizes Schottky gates, placed on the sides of a shallow etched
quantum dot, to control the electronic transport process. An adjacent quantum
point contact gate is integrated to the side gates to define a read-out channel
and thus allow for noninvasive detection of the electronic occupation of the
quantum dot. Reproducible and stable Coulomb oscillations and the corresponding
jumps in the read-out channel resistance are observed at low temperatures. The
fabricated dot combined with the read-out channel represent a step towards the
spin-based quantum bit in Si/SiGe heterostructures.Comment: 3 pages, 4 fig
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