Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spectroscopic and first principle DFT+eDMFT study of complex structural,
  electronic, and vibrational properties of $M_2$Mo$_3$O$_8$ ($M$=Fe, Mn) polar
  magnets   Optical spectroscopy, X-ray diffraction measurements, density functional
theory (DFT) and density functional theory + embedded dynamical mean field
theory (DFT+eDMFT) have been used to characterize structural and electronic
properties of hexagonal $M_2$Mo$_3$O$_8$ ($M$=Fe, Mn) polar magnets. Our
experimental data are consistent with the room temperature structure belonging
to the space group P6$_3$mc for both compounds. The experimental structural and
electronic properties at room temperature are well reproduced within DFT+eDMFT
method, thus establishing its predictive power in the paramagnetic phase. With
decreasing temperature, both compounds undergo a magnetic phase transition and
we argue that this transition is concurrent with a structural phase transition
(symmetry change from P6$_3$mc) in the Fe compound and an isostructural
transition (no symmetry change from P6$_3$mc) in the Mn compound. In addition,
the unusual temperature dependent behavior of electronic d-d transitions in
Fe$^{2+}$ ions is discussed.

8
The categories of this paper are: hep-ex
21
The categories of this paper are: adap-org
3
The categories of this paper are: physics
35
The categories of this paper are: mtrl-th
29
The categories of this paper are: funct-an
1
The categories of this paper are: cs
37
The categories of this paper are: supr-con
9
The categories of this paper are: nlin
17
The categories of this paper are: q-fin
20
The categories of this paper are: acc-phys
33
The categories of this paper are: plasm-ph
32
The categories of this paper are: atom-ph
0
The categories of this paper are: hep-ph
36
The categories of this paper are: cmp-lg
26
The categories of this paper are: bayes-an
10
The categories of this paper are: q-bio