  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.
