Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dynamical Study of the Origin of the Charge Density Wave in
  $A$V$_{3}$Sb$_{5}$ ($A=$K, Rb, Cs) Compounds   Systems containing the ideal kagome lattice can exhibit several distinct and
novel exotic states of matter. One example of such systems is a recently
discovered $A$V$_{3}$Sb$_{5}$ ($A$ = K, Rb, and Cs) family of compounds. Here,
the coexistence of the charge density wave (CDW) and superconductivity is
observed. In this paper, we study the dynamic properties of the
$A$V$_{3}$Sb$_{5}$ systems in context of origin of the CDW phase. We show and
discuss the structural phase transition from $P6/mmm$ to $C2/m$ symmetry that
are induced by the presence of phonon soft modes. We conclude that the CDW
observed in this family of compounds is a consequence of the atom displacement,
from the high symmetry position of the kagome net, in low-temperature phase.
Additionally, using the numerical {\it ab initio} methods, we discuss the
charge distribution on the $A$V$_{3}$Sb$_{5}$ surface. We show that the
observed experimental %$4\times 1$ stripe-like modulation of the surface, can
be related to surface reconstruction and manifestation of the three dimensional
$2 \times 2 \times 2$ bulk CDW. Finally, the consequence of realization of the
$C2/m$ structure on the electronic properties are discussed. We show that the
electronic band structure reconstruction and the accompanying modification of
density of states correspond well to the experimental data.

9
The categories of this paper are: nlin
5
The categories of this paper are: gr-qc
35
The categories of this paper are: mtrl-th
7
The categories of this paper are: hep-th
22
The categories of this paper are: chao-dyn
29
The categories of this paper are: funct-an
24
The categories of this paper are: dg-ga
2
The categories of this paper are: math
36
The categories of this paper are: cmp-lg
26
The categories of this paper are: bayes-an
13
The categories of this paper are: quant-ph
6
The categories of this paper are: astro-ph
25
The categories of this paper are: patt-sol
17
The categories of this paper are: q-fin
12
The categories of this paper are: nucl-th
8
The categories of this paper are: hep-ex