Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: First-principles investigation of graphitic carbon nitride monolayer
  with embedded Fe atom   Density-functional theory calculations with spin-polarized generalized
gradient approximation and Hubbard $U$ correction is carried out to investigate
the mechanical, structural, electronic and magnetic properties of graphitic
heptazine with embedded $\mathrm{Fe}$ atom under bi-axial tensile strain and
applied perpendicular electric field. It was found that the binding energy of
heptazine with embedded $\mathrm{Fe}$ atom system decreases as more tensile
strain is applied and increases as more electric field strength is applied. Our
calculations also predict a band gap at a peak value of 5 tensile strain but at
expense of the structural stability of the system. The band gap opening at 5
tensile strain is due to distortion in the structure caused by the repulsive
effect in the cavity between the lone pairs of edge nitrogen atoms and
$\mathrm{d}_{{xy}}/\mathrm{d}_{x^2-y^2}$ orbital of Fe atom, hence the
unoccupied $\mathrm{p}_z$-orbital is forced to shift towards higher energy. The
electronic and magnetic properties of the heptazine with embedded $\mathrm{Fe}$
system under perpendicular electric field up to a peak value of 10
$\mathrm{V/nm}$ is also well preserved despite obvious buckled structure. Such
properties may be desirable for diluted magnetic semiconductors, spintronics,
and sensing devices.

37
The categories of this paper are: supr-con
28
The categories of this paper are: alg-geom
7
The categories of this paper are: hep-th
2
The categories of this paper are: math
13
The categories of this paper are: quant-ph
22
The categories of this paper are: chao-dyn
16
The categories of this paper are: stat
20
The categories of this paper are: acc-phys
35
The categories of this paper are: mtrl-th
29
The categories of this paper are: funct-an
3
The categories of this paper are: physics
23
The categories of this paper are: solv-int
6
The categories of this paper are: astro-ph
14
The categories of this paper are: math-ph
32
The categories of this paper are: atom-ph
18
The categories of this paper are: econ