Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Anomalous polarization dependence of Raman scattering and
  crystallographic orientation of black phosphorus   We investigated polarization dependence of the Raman modes in black
phosphorus (BP) using five different excitation wavelengths. The
crystallographic orientation was determined by comparing polarized optical
microscopy with high-resolution transmission electron microscope analysis. In
polarized Raman spectroscopy, the B2g mode shows the same polarization
dependence regardless of the excitation wavelength or the sample thickness. On
the other hand, the Ag1 and Ag2 modes show a peculiar polarization behavior
that depends on the excitation wavelength and the sample thickness. The
thickness dependence can be explained by considering the anisotropic
interference effect due to birefringence and dichroism of the BP crystal, but
the wavelength dependence cannot be explained. We propose a simple and
fail-proof procedure to determine the orientation of a BP crystal by combining
polarized Raman scattering with polarized optical microscopy.

22
The categories of this paper are: chao-dyn
2
The categories of this paper are: math
18
The categories of this paper are: econ
6
The categories of this paper are: astro-ph
7
The categories of this paper are: hep-th
30
The categories of this paper are: q-alg
23
The categories of this paper are: solv-int
0
The categories of this paper are: hep-ph
35
The categories of this paper are: mtrl-th
37
The categories of this paper are: supr-con
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The categories of this paper are: adap-org
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The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an
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The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
3
The categories of this paper are: physics