Raman signatures of pressure induced electronic topological and structural transitions in Bi2Te3

TL;DR

This study identifies Raman spectral signatures associated with pressure-induced electronic and structural transitions in Bi2Te3, revealing new vibrational modes and changes in phonon behavior at specific pressures.

Contribution

It provides the first detailed Raman analysis of both electronic topological and structural transitions in Bi2Te3 under pressure.

Findings

Raman mode near 107 cm-1 appears at 3.6 GPa indicating ETT

Structural transition at ~8 GPa marked by new Raman modes and frequency changes

Grüneisen parameters are calculated for both phases

Abstract

We report Raman signatures of electronic topological transition (ETT) at 3.6 GPa and rhombohedral ({\alpha}-Bi2Te3) to monoclinic ({\beta}-Bi2Te3) structural transition at ~ 8 GPa. At the onset of ETT, a new Raman mode appears near 107 cm-1 which is dispersionless with pressure. The structural transition at ~ 8 GPa is marked by a change in pressure derivative of A1g and Eg mode frequencies as well as by appearance of new modes near 115 cm-1and 135 cm-1. The mode Gr\"uneisen parameters are determined in both the {\alpha} and {\beta}-phases.