Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Phonon dynamics and thermal conductivity of PtSe2 thin films: Impact of
  crystallinity and film thickness on heat dissipation   We present a comparative investigation of the influence of crystallinity and
film thickness on the acoustic and thermal properties of 2D layered PtSe2 thin
films of varying thickness (0.6-24 nm) by combining a set of experimental
techniques, namely, frequency domain thermo-reflectance, low-frequency Raman
and pump-probe coherent phonon spectroscopy. We find a 35% reduction in the
cross-plane thermal conductivity of polycrystalline films with thickness larger
than 12 nm compared to the crystalline films of the same thickness due to
phonon grain boundary scattering. Density functional theory calculations are in
good agreement with the experiments and further reveal the ballistic nature of
cross-plane heat transport in PtSe2 up to a certain thickness (~20 nm). In
addition, our experiments revealed strong interlayer interactions in PtSe2,
short acoustic phonon lifetimes in the range of picoseconds, out-of-plane
elastic constant C33=31.8 GPa and layer-dependent group velocity ranging from
1340 m/s in bilayer PtSe2 to 1873 m/s in 8 layers of PtSe2. The potential of
tuning the lattice cross-plane thermal conductivity of layered 2D materials
with the level of crystallinity and the real-time observation of coherent
phonon dynamics, which have direct implications on the cooling and transport of
electrons, open a new playground for research in 2D thermoelectric devices and
provide guidelines for thermal management in 2D electronics.

8
The categories of this paper are: hep-ex
27
The categories of this paper are: comp-gas
25
The categories of this paper are: patt-sol
34
The categories of this paper are: chem-ph
24
The categories of this paper are: dg-ga
2
The categories of this paper are: math
30
The categories of this paper are: q-alg
31
The categories of this paper are: ao-sci
36
The categories of this paper are: cmp-lg
29
The categories of this paper are: funct-an
33
The categories of this paper are: plasm-ph
26
The categories of this paper are: bayes-an
37
The categories of this paper are: supr-con
11
The categories of this paper are: hep-lat
21
The categories of this paper are: adap-org
14
The categories of this paper are: math-ph