PNNL

Abstract

Multiferroic materials host both ferroelectricity and magnetism and provide compelling platforms for future applications in magnetic memory and spin transistors. The recent discovery of multiferroicity in the two-dimensional (2D) transition metal halide NiI2 and chalcogenide CuCrP2S6 overcomes the size effect of traditional multiferroics and may enable the development of 2D multiferroic devices. This advancement stimulates a search for diverse layered multiferroic chalcogenides and halides. Here we report a new multiferroic layered chalcogenide semiconductor CuMnSiTe3. This material crystallizes into a polar monoclinic crystal structure with the space group of Cm and displays a sequence of magnetic transitions, with its long-range antiferromagnetic (AFM) order appearing at ~35 K and changing into a canted AFM state with distinct magnetic hysteresis and remanent magnetization below ~15 K. We demonstrate multiferroicity and strong magnetoelectric coupling through magnetodielectric and magnetocurrent measurements. The magnetically induced electric polarization at 10 K reaches ~0.8 µC/cm2, comparable to the highest value in oxide multiferroics. We also observe evidence for possible room-temperature ferroelectricity from piezoresponse force microscopy. Given that multiferroicity is very rare among transition metal chalcogenides, our finding sets up a new materials platform for designing new layered multiferroic chalcogenides.