Crystal Growth, Structural Analysis, and Pressure-Induced Superconductivity in a AgIn₅Se₈ Single Crystal Explored by...

A high-throughput first-principles calculation-assisted data-driven approach based on an inorganic materials database named AtomWork was performed to explore new superconducting materials. Specific band structures of a small band gap and flat band at band edges were used in a screening procedure. Among the candidates studied, we focused on AgIn₅Se₈, which shows a high density of state at the Fermi level. Single crystals of AgIn₅Se₈ were successfully obtained via a melt and slow cooling method. The valence states in AgIn₅Se₈ were estimated to be Ag¹⁺, In³⁺, and Se^2- using X-ray photoelectron spectroscopy. An electrical transport property of resistance was measured under high pressure using an electrodes-inserted diamond anvil cell. The sample exhibited an insulator-to-metal transition with a drastic decrease of the resistance by increasing the pressure up to 24.8 GPa. A possibility of a pressure-driven phase transition below this pressure was indicated by an enthalpy calculation. At a higher pressure region of 52.5 GPa, a pressure-induced superconducting transition was observed at 3.4 K. The maximum transition temperature was increased up to 3.7 K under the pressure of 74.0 GPa.