Exploring the Magnetic Ground State and Electric Control in Two-Dimensional Multiferroics*

Two-dimensional magnets have recently gained significant attention due to their unique properties and high tunability compared to their bulk counterparts. Among these materials, type-II 2D multiferroics have emerged as intriguing systems that exhibit rich physics arising from the interaction between a chiral helical magnetic order and a magnetism-induced ferroelectric order. Motivated by the experimental discovery of a single-layer multiferroic in the NiI2 system, our study focuses on investigating the magnetic ground state of NiI2 under the combined influence of electrostatic doping and an electric field in a single-gate device structure. To elucidate the dynamics of electric and magnetic orders, we employ photocurrent and linear dichroism measurements. Remarkably, we observe a pronounced photocurrent upon applying gate voltage, displaying asymmetric voltage dependence. Furthermore, we observe the emergence of a possibly novel state at intermediate temperature, which has not been previously observed. These findings not only provide valuable insights into the behavior of 2D multiferroics, chiral magnetic textures, and magnetoelectric coupling but also hold promise for potential applications in magneto-electric devices. We will present a comprehensive analysis of the electric control over the magnetic ground state in NiI2, shedding light on the underlying mechanisms and offering new avenues for exploring 2D multiferroics and their technological potential.