Coexistence of polar structural character and superconductivity in pressurized CuInP2Se6 single crystal

Abstract

Pressurization is a common method for regulating the crystal structure and physical properties of materials without altering their chemical composition. In this work, the two-dimensional (2D) CuInP2Se6 single crystal was prepared using a P2Se5 reactive-flux method. The pressure-driven phase transition and evolution of ferroelectric-to-superconductor in CuInP2Se6 was demonstrated. A systematic structural transformation from the hexagonal (P31c, No. 159) phase to monoclinic (Cc, No. 9) phase and hexagonal (P31c, No. 159) phase was observed at 10 GPa and 35 GPa, respectively. Superconductivity emerged in CuInP2Se6 at 35 GPa, potentially competing with its intrinsic polarity. These discoveries on pressurized CuInP2Se6 offer insight into the interaction of crystalline structure and electrical properties under high-pressure conditions.