Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Nitride Multilayers as a Platform for Parallel Two-Dimensional
  Electron-Hole Gases: MgO/ScN(111)   At interfaces between insulating oxides LaAlO$_3$ and SrTiO$_3$, a two
dimensional electron gas (2DEG) has been observed and well studied, while the
predicted hole gas (2DHG) has not been realized due to the strong tendency of
holes in oxygen $2p$ orbitals to localize. Here we propose, via ab initio
calculations, an unexplored class of materials for the realization of parallel
two dimensional (2D), two carrier (electron+hole) gases: nitride-oxide
heterostructures, with (111)-oriented ScN and MgO as the specific example.
Beyond a critical thickness of five ScN layers, this interface hosts spatially
separated conducting Sc-$3d$ electrons and N-$2p$ holes, each confined to
$\sim$two atomic layers -- the transition metal nitride provides both gases. A
guiding concept is that the N$^{3-}$ anion should promote robust two carrier 2D
hole conduction compared to that of O$^{2-}$; metal mononitrides are mostly
metallic and even superconducting while most metal monoxides are insulating. A
second positive factor is that the density of transition metal ions, hence of a
resulting 2DG, is about three times larger for a rocksalt (111) interface than
for a perovskite(001) interface. Our results, including calculation of Hall
coefficient and thermopower for each conducting layer separately, provide
guidance for new exploration, both experimental and theoretical, on
nitride-based conducting gases that should promote study of long sought exotic
states viz. new excitonic phases and distinct, nanoscale parallel
superconducting nanolayers.

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The categories of this paper are: bayes-an
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The categories of this paper are: chao-dyn
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The categories of this paper are: funct-an
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The categories of this paper are: econ
10
The categories of this paper are: q-bio
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The categories of this paper are: adap-org
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The categories of this paper are: math-ph
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The categories of this paper are: q-alg
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The categories of this paper are: acc-phys
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The categories of this paper are: ao-sci
13
The categories of this paper are: quant-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: supr-con
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The categories of this paper are: dg-ga
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The categories of this paper are: alg-geom
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The categories of this paper are: nucl-th