Sb₂Se₃ under pressure.

Area of Science:

• Condensed Matter Physics
• Materials Science
• High-Pressure Physics

Background:

• The A₂B₃ (A = Sb, Bi; B = Se, Te) family includes known topological insulators.
• Antimony selenide (Sb₂Se₃) was previously suggested to become a topological insulator above 2 GPa, with multiple structural transitions.
• Understanding Sb₂Se₃'s behavior under pressure is crucial for exploring its potential topological properties.

Purpose of the Study:

• To investigate the structural phase transitions of Sb₂Se₃ under high pressure.
• To clarify the discrepancies in previous high-pressure studies on Sb₂Se₃.
• To determine the pressure-induced structural evolution of Sb₂Se₃ up to 65 GPa.

Main Methods:

• High-pressure X-ray diffraction (XRD) up to 65 GPa.
• High-pressure Raman spectroscopy up to 65 GPa.
• Analysis of structural transitions and phase stability.

Main Results:

• Identified a single reversible structural transition in Sb₂Se₃.
• The initial Pnma structure transforms into a disordered cubic bcc alloy above 51 GPa.
• High-pressure Raman spectroscopy results differed from prior studies, attributed to pressure-transmitting media.

Conclusions:

• Sb₂Se₃ undergoes a significant structural transformation to a disordered cubic phase at high pressures.
• The study provides a revised understanding of Sb₂Se₃'s structural behavior, differing from previous reports on topological transitions.
• The choice of pressure-transmitting medium significantly impacts high-pressure Raman spectroscopy results for Sb₂Se₃.