Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Resonant tunneling-based spin ratchets   We outline a generic ratchet mechanism for creating directed spin-polarized
currents in ac-driven double well or double dot structures by employing
resonant spin transfer through the system engineered by local external magnetic
fields. We show its applicability to semiconductor nanostructures by
considering coherent transport through two coupled lateral quantum dots, where
the energy levels of the two dots exhibit opposite Zeeman spin splitting. We
perform numerical quantum mechanical calculations for the I-V characteristics
of this system in the nonlinear regime, which requires a self-consistent
treatment of the charge redistribution due to the applied finite bias. We show
that this setting enables nonzero averaged net spin currents in the absence of
net charge transport.

25
The categories of this paper are: patt-sol
17
The categories of this paper are: q-fin
9
The categories of this paper are: nlin
11
The categories of this paper are: hep-lat
18
The categories of this paper are: econ
29
The categories of this paper are: funct-an
20
The categories of this paper are: acc-phys
1
The categories of this paper are: cs
23
The categories of this paper are: solv-int
15
The categories of this paper are: nucl-ex
34
The categories of this paper are: chem-ph
6
The categories of this paper are: astro-ph
12
The categories of this paper are: nucl-th
10
The categories of this paper are: q-bio
36
The categories of this paper are: cmp-lg
2
The categories of this paper are: math