Electron-phonon interactions and tensor analysis in topological insulator bismuth telluride using angle resolved polarized Raman spectroscopy

TL;DR

This study uses angle-resolved polarized Raman spectroscopy to analyze electron-phonon interactions and tensor properties in Bismuth Telluride, revealing anisotropic polarizability and photon-phonon interactions relevant to its topological and thermoelectric features.

Contribution

It introduces a combined classical and quantum approach to estimate Raman tensor elements and analyze lattice dynamics in Bismuth Telluride.

Findings

Higher differential polarizability along the c-axis.

Anisotropic photon-phonon interactions observed.

Systematic variation in Raman mode intensities.

Abstract

We report on the angle-resolved polarized Raman spectroscopy and estimation of the Raman tensor elements using both classical and quantum treatments to analyse the polarized Raman spectra of single crystal Bismuth Telluride. The observed polar patterns and systematic variations in the relative intensities of four characteristic Raman active modes indicate a higher differential polarizability along the c-axis, accompanied by anisotropic photon-phonon interactions. This interplay of electron-photon-phonon interactions is crucial for understanding the lattice dynamics of Bismuth Telluride, which underpin its thermoelectric performance and topological properties.