Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Stress modulated optical spin-injection in bulk semiconductors   A full band-structure ab initio calculation of the degree of spin
polarization (DSP) in stressed bulk Si and bulk GaAs is reported. For Si, we
found that compressive stress causes the DSP signal peak to decrease slightly
in magnitude and to shift to higher energies.

18
The categories of this paper are: econ
17
The categories of this paper are: q-fin
24
The categories of this paper are: dg-ga
27
The categories of this paper are: comp-gas
0
The categories of this paper are: hep-ph
32
The categories of this paper are: atom-ph
9
The categories of this paper are: nlin
20
The categories of this paper are: acc-phys
36
The categories of this paper are: cmp-lg
5
The categories of this paper are: gr-qc
37
The categories of this paper are: supr-con
12
The categories of this paper are: nucl-th
14
The categories of this paper are: math-ph
30
The categories of this paper are: q-alg
8
The categories of this paper are: hep-ex
33
The categories of this paper are: plasm-ph