502 research outputs found
Plasma assisted fabrication of zinc oxide based nanostructures
ZnO/Ag nanocomposite structures were prepared by using a discharge with an atmospheric-pressure mi-croplasma cathode and a solid metal anode immersed in an electrolyte solution and their properties were studied. The effect of Ag on the microstructure and optical properties of ZnO has been discussed
Ultrastructure of meristem and root cap of pea seedlings under spaceflight conditions
Data of electron microscopic analysis of meristem and root cap of pea seedlings grown aboard the Salyut-6 orbital research station in the Oazis apparatus and in the laboratory are presented. The main morphological and anatomical characteristics of the test and control plants are shown to be similar. At the same time, some differences are found in the structural and functional organization of the experimental cells as compared to the controls. They concern first of all the plastic apparatus, mitochondria and Golgi apparatus. It is assumed that cell function for certain periods of weightlessness on the whole ensures execution of the cytodifferentiation programs genetically determined on the Earth. Biochemical and physiological processes vary rather markedly due to lack of initially rigorous determination
Spin-orbit Hanle effect in high-mobility quantum wells
We study the depolarization of optically oriented electrons in quantum wells
subjected to an in-plane magnetic field and show that the Hanle curve
drastically depends on the carrier mobility. In low-mobility structures, the
Hanle curve is described by a Lorentzian with the width determined by the
effective g-factor and the spin lifetime. In contrast, the magnetic field
dependence of spin polarization in high-mobility quantum wells is nonmonotonic:
The spin polarization rises with the magnetic field induction at small fields,
reaches maximum and then decreases. We show that the position of the Hanle
curve maximum can be used to directly measure the spin-orbit Rashba/Dresselhaus
magnetic field.Comment: 4 pages, 3 figure
Valley separation in graphene by polarized light
We show that the optical excitation of graphene with polarized light leads to
the pure valley current where carriers in the valleys counterflow. The current
in each valley originates from asymmetry of optical transitions and electron
scattering by impurities owing to the warping of electron energy spectrum. The
valley current has strong polarization dependence, its direction is opposite
for normally incident beams of orthogonal linear polarizations. In undoped
graphene on a substrate with high susceptibility, electron-electron scattering
leads to an additional contribution to the valley current that can dominate.Comment: 4+ pages, 2 figure
Tunneling spin-galvanic effect
It has been shown that tunneling of spin-polarized electrons through a
semiconductor barrier is accompanied by generation of an electric current in
the plane of the interfaces. The direction of this interface current is
determined by the spin orientation of the electrons, in particular the current
changes its direction if the spin orientation changes the sign. Microscopic
origin of such a 'tunneling spin-galvanic' effect is the spin-orbit
coupling-induced dependence of the barrier transparency on the spin orientation
and the wavevector of electrons.Comment: 3 pages, 2 figure
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