AgInP₂S₆ (Silver Indium Phosphorus Trisulfide)

A layered van der Waals metal phosphochalcogenide isostructural with CuInP₂S₆, in which Ag⁺ and In³⁺ cations occupy the octahedral sites of the P₂S₆ framework. It is a wide-bandgap semiconductor that exhibits candidate two-dimensional ferroelectric / antiferroelectric polar order owing to the displacement tendency of the Ag⁺ ions, which persists to few-layer thickness. The combination of a wide bandgap and tunable polarization makes AgInP₂S₆ a candidate for studying two-dimensional ferroelectrics, dielectric layers, and optoelectronic applications.