Pressure-induced enhancement of the superconducting transition temperature in La2O2Bi3AgS6

Charge density wave (CDW) instability is often found in phase diagrams of superconductors such as cuprates and certain transition-metal dichalcogenides. This proximity to superconductivity triggers the question on whether CDW instability is responsible for the pairing of electrons in these superconductors. However, this issue remains unclear and new systems are desired to provide a better picture. Here, we report the temperature-pressure phase diagram of a recently discovered BiS2 superconductor La2O2Bi3AgS6, which shows a possible CDW transition at T* similar to 155 K and a superconducting transition at T ( c ) similar to 1.0 K at ambient pressure, via electrical resistivity measurements. Upon applying pressure, T* decreases linearly and extrapolates to 0 K at 3.9 GPa. Meanwhile, T ( c ) is enhanced and reaches maximum value of 4.1 K at 3.1 GPa, forming a superconducting dome in the temperature-pressure phase diagram.

Automated summary

Charge density wave (CDW) instability is commonly found in superconductors, but its relationship with the pairing of electrons remains unclear. This study investigates a BiS2 superconductor and reveals the presence of CDW and superconducting transitions in the temperature-pressure phase diagram, suggesting a possible connection between CDW and electron pairing.