152,519 research outputs found
Plasmon spectrum of two-dimensional electron systems with Rashba spin-orbit interaction
The dielectric function and plasmon modes of a two-dimensional electron gas
(2DEG) are studied in single- and double-quantum-well structures with Rashba
spin-orbit interaction (RSOI) in the framework of the random-phase
approximation. The RSOI splits each parabolic energy subband of a 2DEG into two
nonparabolic spin branches and affects the electronic many-body correlation and
dielectric properties of the 2DEG. The influence of the RSOI on the 2DEG
plasmon spectrum in single quantum wells appear mainly in three ways: 1) an
overall frequency lowering due to the energy band deformation; 2) a weak
frequency oscillation stemming from the spin-split energy band; and 3)an
enhancement of the Landau damping as a result of the emerging of the
inter-branch single-particle-excitation spectrum. In double quantum wells, the
above effects are enhanced for the optic plasmon mode but diminished for the
acoustic one.Comment: 7 figure
Ballistic spin transport through electronic stub tuners: spin precession, selection, and square-wave transmission
Ballistic spin transport is studied through electronic tuners with double
stubs attached to them. The spins precess due to the spin-orbit interaction.
Injected polarized spins can exit the structure polarized in the opposite
direction. A nearly square-wave spin transmission, with values 1 and 0, can be
obtained using a periodic system of symmetric stubs and changing their length
or width. The gaps in the transmission can be widened using asymmetric stubs.
An additional modulation is obtained upon combining stub structures with
different values of the spin-orbit strength.Comment: 3 pages, 4 figure
X-Ray Flares from Postmerger Millisecond Pulsars
Recent observations support the suggestion that short-duration gamma-ray
bursts are produced by compact star mergers. The X-ray flares discovered in two
short gamma-ray bursts last much longer than the previously proposed postmerger
energy release time scales. Here we show that they can be produced by
differentially rotating, millisecond pulsars after the mergers of binary
neutron stars. The differential rotation leads to windup of interior poloidal
magnetic fields and the resulting toroidal fields are strong enough to float up
and break through the stellar surface. Magnetic reconnection--driven explosive
events then occur, leading to multiple X-ray flares minutes after the original
gamma-ray burst.Comment: 10 pages, published in Scienc
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