954 research outputs found
Coherent Single Spin Source based on topological insulator
We report on the injection of quantized pure spin current into quantum
conductors. In particular, we propose an on demand single spin source generated
by periodically varying the gate voltages of two quantum dots that are
connected to a two dimensional topological insulator via tunneling barriers.
Due to the nature of the helical states of the topological insulator, one or
several {\it spin pair}s can be pumped out per cycle giving rise to a pure
quantized alternating spin current. Depending on the phase difference between
two gate voltages, this device can serve as an on demand single spin emitter or
single charge emitter. Again due to the helicity of the topological insulator,
the single spin emitter or charge emitter is dissipationless and immune to
disorders. The proposed single spin emitter can be an important building block
of future spintronic devices.Comment: 5 pages, 4 figures, append one co-author that has been misse
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