Anisotropic Raman scattering and lattice orientation identification of 2M-WS2

TL;DR

This study combines theoretical and experimental methods to analyze anisotropic Raman modes in 2M-WS2, enabling accurate crystal orientation identification and providing insights into its anisotropic properties relevant for quantum device applications.

Contribution

It introduces a reliable Raman spectroscopy-based method for determining crystal orientation in 2M-WS2, supported by first-principles calculations and microscopy correlation.

Findings

Anisotropic Raman spectra correlate with lattice orientation.

Raman spectroscopy can determine twist angles in stacked layers.

The study enhances understanding of electron-phonon interactions in 2M-WS2.

Abstract

Anisotropic materials with low symmetries hold significant promise for next-generation electronic and quantum devices. 2M-WS2, a candidate for topological superconductivity, has garnered considerable interest. However, a comprehensive understanding of how its anisotropic features contribute to unconventional superconductivity, along with a simple, reliable method to identify its crystal orientation, remains elusive. Here, we combine theoretical and experimental approaches to investigate angle- and polarization-dependent anisotropic Raman modes of 2M-WS2. Through first-principles calculations, we predict and analyze phonon dispersion and lattice vibrations of all Raman modes in 2M-WS2. We establish a direct correlation between their anisotropic Raman spectra and high-resolution transmission electron microscopy images. Finally, we demonstrate that anisotropic Raman spectroscopy can accurately determine the crystal orientation and twist angle between two stacked 2M-WS2 layers. Our findings provide insights into the electron-phonon coupling and anisotropic properties of 2M-WS2, paving the way for the use of anisotropic materials in advanced electronic and quantum devices.