Observation of Structural and Electronic Transitions in Bimetallic Chalcogenide of Copper Tantalum Trisulfide via Pressure Engineering

CuTaS 3, an important member of the bimetallic chalcogenide family, stands out because of its nontrivial physicochemical properties and potential applications in electronic and optoelectronic devices. Despite the extensive investigations into structural characterizations and device applications, the knowledge about structural and electronic transitions of CuTaS 3 under high pressure is deficient. In this work, we filled these research gaps and explored the high-pressure structural, vibrational, and electrical transport properties of CuTaS 3 under different hydrostatic environments by virtue of Raman spectroscopy, microarea X-ray diffraction (XRD), and electrical conductivity measurements. Upon nonhydrostatic compression, CuTaS 3 experienced two successive phase transitions at 2.2 and 5.4 GPa and sequential metallization at 12.5 GPa. Nevertheless, the pressure-induced structural and electronic transitions of CuTaS 3 were unsusceptible to hydrostaticity, which was attributed to the faint deviatoric stress at ∼10.0 GPa under different hydrostatic environments. Upon depressurization, the phase transition was revealed to be incompletely reversible under different hydrostatic environments with the preservation of pressure effects or the existence of a kinetic barrier. Additionally, CuTaS 3 exhibited Ohmic behavior at high pressures. These findings on CuTaS 3 pave the way for exploring the physicochemical properties of other bimetallic chalcogenides under extreme conditions, thereby facilitating its potential applications in other promising fields.