449 research outputs found
Non-equilibrium Spin Waves in Paramagnetic Metals
We theoretically study the effect of exchange interaction on the
non-equilibrium spin waves in disordered paramagnetic metals under the spin
injection condition. We show that the gapless spectrum of spin waves,
describing the spin precession in the absence of the applied magnetic field,
changes sign to negative on the paramagnetic side near the ferromagnet -
paramagnet phase transition. The damping of spin waves is small in the limit
when electron-electron exchange energy is larger than the inverse electron mean
free time, while in the opposite limit the propagation of spin waves is
strongly suppressed. We discuss the amplification of the electromagnetic field
by the non-equilibrium spin waves.Comment: 6 pages, 3 figure
Mesoscopic oscillations of the conductance of disordered metallic samples as a function of temperature
We show theoretically and experimentally that the conductance of small
disordered samples exhibits random oscillations as a function of temperature.
The amplitude of the oscillations decays as a power law of temperature, and
their characteristic period is of the order of the temperature itself
Thin topological insulator film in a perpendicular magnetic field
We report on a study of an ultrathin topological insulator film with
hybridization between the top and bottom surfaces, placed in a quantizing
perpendicular magnetic field. We calculate the full Landau level spectrum of
the film as a function of the applied magnetic field and the magnitude of the
hybridization matrix element, taking into account both the orbital and the
Zeeman spin splitting effects of the field. For an undoped film, we find a
quantum phase transition between a state with a zero Hall conductivity and a
state with a quantized Hall conductivity equal to , as a function of the
magnitude of the applied field. The transition is driven by the competition
between the Zeeman and the hybridization energies.Comment: 4+ pages, 1 figure, published versio
Spin injection dependent metamagnetic transition
We define the metamagnetic phase transition of itinerant electrons controlled
by the spin injection mechanism. The current flow between a ferromagnetic metal
and a metamagnetic metal produces the non-equilibrium shift of chemical
potential for spin up and spin down electrons that acts as an effective
magnetic field driving the metamagnetic transition.Comment: 6 pages, 3 figure
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