Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spin relaxation via exchange with donor impurity-bound electrons   At low temperatures, electrons in semiconductors are bound to shallow donor
impurity ions, neutralizing their charge in equilibrium. Inelastic scattering
of other externally-injected conduction electrons accelerated by electric
fields can excite transitions within the manifold of these localized states.
Promotion of the bound electron into highly spin-orbit-mixed excited states
drives a strong spin relaxation of the conduction electrons via exchange
interactions, reminiscent of the Bir-Aronov-Pikus process where exchange occurs
with valence band hole states. Through low-temperature experiments with silicon
spin transport devices and complementary theory, we reveal the consequences of
this previously unknown spin depolarization mechanism both below and above the
impact ionization threshold.

2
The categories of this paper are: math
10
The categories of this paper are: q-bio
28
The categories of this paper are: alg-geom
18
The categories of this paper are: econ
21
The categories of this paper are: adap-org
13
The categories of this paper are: quant-ph
22
The categories of this paper are: chao-dyn
30
The categories of this paper are: q-alg
8
The categories of this paper are: hep-ex
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The categories of this paper are: cmp-lg
0
The categories of this paper are: hep-ph
31
The categories of this paper are: ao-sci
32
The categories of this paper are: atom-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: comp-gas
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The categories of this paper are: funct-an