Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Brightening of dark excitons in monolayers of semiconducting transition
  metal dichalcogenides   We present low temperature magneto-photoluminescence experiments which
demonstrate the brightening of dark excitons by an in-plane magnetic field $B$
applied to monolayers of different semiconducting transition metal
dichalcogenides. For both WSe$_2$ and WS$_2$ monolayers, the dark exciton
emission is observed at $\sim$50 meV below the bright exciton peak and displays
a characteristic doublet structure which intensity is growing with $B^2$, while
no magnetic field induced emission peaks appear for MoSe$_2$ monolayer. Our
experiments also show that the MoS$_2$ monolayer has a dark exciton ground
state with a dark-bright exciton splitting energy of $\sim$100 meV.

31
The categories of this paper are: ao-sci
25
The categories of this paper are: patt-sol
15
The categories of this paper are: nucl-ex
29
The categories of this paper are: funct-an
6
The categories of this paper are: astro-ph
28
The categories of this paper are: alg-geom
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The categories of this paper are: dg-ga
26
The categories of this paper are: bayes-an
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The categories of this paper are: chem-ph
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The categories of this paper are: adap-org
11
The categories of this paper are: hep-lat
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The categories of this paper are: cmp-lg
12
The categories of this paper are: nucl-th
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The categories of this paper are: hep-th
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The categories of this paper are: chao-dyn
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The categories of this paper are: q-alg