Pressure-Induced Dome-Like Superconductivity and Unusual Charge-Density-Wave-Like Transition in Th2Cu4As5

The recently discovered Cu4As3-type material Th2Cu4As5 has been reported to exhibit both superconductivity and charge density wave (CDW) orders. These two electronic phenomena might originate from distinct structural units in Th2Cu4As5, providing a unique platform to investigate the interplay between superconductivity and CDW. In this work, we carried out high-pressure electrical transport and X-ray diffraction measurements to track the evolution of the CDW and superconductivity at high pressure. Superconductivity can initially be enhanced upon the suppression of the CDW transition and then gradually decrease with increasing pressure after the CDW transition is completely suppressed, displaying a characteristic dome-like behavior. More intriguingly, a 2 × 2 × 5 superlattice appears at pressures exceeding 8 GPa, which coincides with the sudden loss of superconductivity. This observation indicates the presence of an unusual possible CDW state that may be linked to the Cu4As3 superconducting layer. Our results unveil versatile CDW states in pressurized Th2Cu4As5, which provide us with a rare platform to investigate the interplay of multiple electronic ordered states.