Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ising superconductivity in monolayer niobium dichalcogenide alloys   NbSe$_{2}$ and NbS$_{2}$ are isostructural two-dimensional materials that
exhibit contrasting superconducting properties when reduced to the single
monolayer limit. Monolayer NbSe$_{2}$ is an Ising superconductor, while there
have been no reports of superconductivity in monolayer NbS$_{2}$.
NbS$_{x}$Se$_{2-x}$ alloys exhibit an intriguing non-monotonic dependence of
the superconducting transition temperature with sulfur content, which has been
interpreted as a manifestation of fractal superconductivity. However, several
key questions about this result are not known: (1) Does the electronic
structure of the alloy differ from the parent compounds, (2) Are spin
fluctuations which have been shown to be prominent in monolayer NbSe$_{2}$ also
present in the alloys? Using first-principles calculations, we show that the
density of states at the Fermi level and the proximity to magnetism in
NbS$_{x}$Se$_{2-x}$ alloys are both reduced compared to the parent compound;
the former would decrease the transition temperature while the latter would
increase it. We also show that Se vacancies, which are likely magnetic
pair-breaking defects, may form in large concentrations in NbSe$_{2}$. Based on
our results, we suggest an alternative explanation of the non-monotonic
behavior the superconducting transition temperature in NbS$_{x}$Se$_{2-x}$
alloys, which does not require the conjecture of multifractality.

2
The categories of this paper are: math
3
The categories of this paper are: physics
34
The categories of this paper are: chem-ph
21
The categories of this paper are: adap-org
5
The categories of this paper are: gr-qc
7
The categories of this paper are: hep-th
12
The categories of this paper are: nucl-th
31
The categories of this paper are: ao-sci
37
The categories of this paper are: supr-con
35
The categories of this paper are: mtrl-th
32
The categories of this paper are: atom-ph
28
The categories of this paper are: alg-geom
11
The categories of this paper are: hep-lat
23
The categories of this paper are: solv-int
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The categories of this paper are: funct-an
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The categories of this paper are: bayes-an