Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Stacking-Dependent Optical Properties in Bilayer WSe2   The twist angle between the monolayers in van der Waals heterostructures
provides a new degree of freedom in tuning material properties. We compare the
optical properties of WSe2 homobilayers with 2H and 3R stacking using
photoluminescence, Raman spectroscopy, and reflectance contrast measurements
under ambient and cryogenic temperatures. Clear stacking- dependent differences
are evident for all temperatures, with both photoluminescence and reflectance
contrast spectra exhibiting a blue shift in spectral features in 2H compared to
3R bilayers. Density functional theory (DFT) calculations elucidate the source
of the variations and the fundamental differences between 2H and 3R stackings.
DFT finds larger energies for both A and B excitonic features in 2H than in 3R,
consistent with experimental results. In both stacking geometries, the
intensity of the dominant A1g Raman mode exhibits significant changes as a
function of laser excitation wavelength. These variations in intensity are
intimately linked to the stacking- and temperature-dependent optical absorption
through resonant enhancement effects. The strongest enhancement is achieved
when the laser excitation coincides with the C excitonic feature, leading to
the largest Raman intensity under 514 nm excitation in 2H stacking and at 520
nm in 3R stacked WSe2 bilayers.

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The categories of this paper are: hep-ph
11
The categories of this paper are: hep-lat
9
The categories of this paper are: nlin
17
The categories of this paper are: q-fin
37
The categories of this paper are: supr-con
35
The categories of this paper are: mtrl-th
7
The categories of this paper are: hep-th
36
The categories of this paper are: cmp-lg
32
The categories of this paper are: atom-ph
33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
13
The categories of this paper are: quant-ph
26
The categories of this paper are: bayes-an
20
The categories of this paper are: acc-phys
12
The categories of this paper are: nucl-th