Pressure induced electronic topological transition in Sb2S3

TL;DR

This study investigates pressure-induced electronic topological transitions in Sb2S3 using Raman spectroscopy and resistivity measurements, revealing phonon softening and resistivity anomalies around 4-5 GPa indicative of a topological change.

Contribution

It provides experimental evidence of electronic topological transition in Sb2S3 under pressure, linking vibrational and transport property changes to Fermi surface topology modifications.

Findings

Phonon mode softening observed at 4 GPa

Resistivity anomaly around 4 GPa

Minimum in a/c ratio at ~5 GPa

Abstract

Pressure induced electronic topological transitions in the wide band gap semiconductor Sb2S3 (Eg = 1.7-1.8 eV) with similar crystal symmetry (SG: Pnma) to its illustrious analog, Sb2Se3, has been studied using Raman spectroscopy, resistivity and the available literature on the x-ray diffraction studies. In this report, the vibrational and the transport properties of Sb2S3 have been studied up to 22 GPa and 11 GPa, respectively. We observed the softening of phonon modes Ag(2), Ag(3) and B2g and a sharp anomaly in their line widths at 4 GPa. The resistivity studies also shows an anomaly around this pressure. The changes in resistivity as well as Raman line widths can be ascribed to the changes in the topology of the Fermi surface which induces the electron-phonon and the strong phonon-phonon coupling, indicating a clear evidence of the electronic topological transition (ETT) in Sb2S3. The pressure dependence of a/c ratio plot obtained from the literature showed a minimum at ~ 5 GPa, which is consistent with our high pressure Raman and resistivity results. Finally, we give the plausible reasons for the non-existence of a non-trivial topological state in Sb2S3 at high pressures.