High-pressure structural phase transition and metallization in Ga2S3 under non-hydrostatic and hydrostatic conditions up to 36.4 GPa

Abstract

The vibrational, electrical and structural properties of gallium sulfide (Ga₂S₃) were explored by Raman spectroscopy, electrical conductivity measurements, high-resolution transmission electron microscopy and first-principles theoretical calculations under different pressure environments up to 36.4 GPa. Upon compression, Ga₂S₃ underwent a first-order structural phase transition accompanied by a semiconductor-to-metal transformation at 17.2 GPa under non-hydrostatic conditions, whereas, the transition occurred at a much lower pressure of 11.3 GPa under hydrostatic conditions because of the influence of the pressure medium. Upon decompression, two possible new high-pressure polymorphs were observed at 8.0 and 3.0 GPa under non-hydrostatic conditions, and similar transition points were obtained under hydrostatic conditions. The structural and electrical transport evolution for Ga₂S₃ upon compression and decompression can help us to deeply understand the high-pressure behaviors of other similar A₂B₃-type structural compounds.