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Polarized Raman spectroscopy in low-symmetry 2D materials: angle-resolved experiments and complex number tensor
Marcos A Pimenta1, Geovani C Resende1, Henrique B Ribeiro2
1Departamento de Física, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais 30123-970, Brazil. mpimenta@fisica.ufmg.br.
Physical Chemistry Chemical Physics : PCCP
|December 3, 2021
Summary
Polarized Raman spectroscopy reveals unique Raman tensors for phonon modes in anisotropic 2D materials. This technique helps determine tensor elements, crucial for understanding their optical properties.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Spectroscopy
Background:
- Optically anisotropic 2D materials exhibit unique properties based on their crystal structure.
- Polarized Raman spectroscopy is a powerful tool for probing these anisotropic materials.
Purpose of the Study:
- To review the application of polarized Raman spectroscopy for studying anisotropic 2D materials.
- To explain how Raman tensors describe polarization-dependent peak intensities.
- To discuss the determination and characteristics of Raman tensors in different crystal systems.
Main Methods:
- Angle-resolved polarized Raman spectroscopy.
- Analysis of parallel- and cross-polarized scattering configurations.
- Quantum model for Raman intensities.
Main Results:
- Raman tensor uniquely describes polarization dependence for each phonon mode.
- Demonstrated analysis for orthorhombic (black phosphorus) and monoclinic (1T'-MoTe2) materials.
- Investigated triclinic (ReS2, ReSe2) materials with non-coinciding tensor axes and non-zero elements.
- Showcased complex nature of Raman tensor elements and phase differences.
- Discussed dependence on laser energy and sample thickness.
Conclusions:
- Polarized Raman spectroscopy provides detailed insights into anisotropic 2D materials.
- Raman tensor analysis is essential for understanding electron-phonon interactions and optical properties.
- Future research can leverage this technique for further exploration of 2D materials.
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