22,155 research outputs found
Activation mechanisms in sodium-doped Silicon MOSFETs
We have studied the temperature dependence of the conductivity of a silicon
MOSFET containing sodium ions in the oxide above 20 K. We find the impurity
band resulting from the presence of charges at the silicon-oxide interface is
split into a lower and an upper band. We have observed activation of electrons
from the upper band to the conduction band edge as well as from the lower to
the upper band. A possible explanation implying the presence of Hubbard bands
is given.Comment: published in J. Phys. : Condens. Matte
Spin polarization control through resonant states in an Fe/GaAs Schottky barrier
Spin polarization of the tunnel conductivity has been studied for Fe/GaAs
junctions with Schottky barriers. It is shown that band matching of resonant
interface states within the Schottky barrier defines the sign of spin
polarization of electrons transported through the barrier. The results account
very well for experimental results including the tunneling of photo-excited
electrons, and suggest that the spin polarization (from -100% to 100%) is
dependent on the Schottky barrier height. They also suggest that the sign of
the spin polarization can be controlled with a bias voltage.Comment: 5 pages, 4 figure
Mesoscopic one-way channels for quantum state transfer via the Quantum Hall Effect
We show that the one-way channel formalism of quantum optics has a physical
realisation in electronic systems. In particular, we show that magnetic edge
states form unidirectional quantum channels capable of coherently transporting
electronic quantum information. Using the equivalence between one-way photonic
channels and magnetic edge states, we adapt a proposal for quantum state
transfer to mesoscopic systems using edge states as a quantum channel, and show
that it is feasible with reasonable experimental parameters. We discuss how
this protocol may be used to transfer information encoded in number, charge or
spin states of quantum dots, so it may prove useful for transferring quantum
information between parts of a solid-state quantum computer.Comment: 4 pages, 3 figure
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