Density Functional Theory Study of Defect Induced Ferromagnetism and Half-Metallicity in CaI2 Based Monolayer for Spintronics Applications

Abstract

With the rapid advancement of electronics and spintronics industries, the demand for highly efficient materials has been increased for the application of high speed devices and circuits. In the recent past, Ca-based systems have been studied for superconducting properties. Using first-principles density functional theoretical calculations, we have investigated another Ca-based system (CaI2) for its half-metallic properties, which can be promising for ultrafast nonscattering transport. In the domain of spintronics, main group based half-metallic materials have attracted much attention due to their long spin-relaxation time. Here, in this study, we report for the first time ferromagnetism and half-metallicity in calcium iodide (CaI2) based materials with a wide spin-up gap of ∼3.84 eV. Such high spin-up gap in Ca-based half-metallic material is very promising since it can provide nonscattering transport. Among all, Ca0.67δ0.33I2 has a similar pattern to the most well established and thinnest magnet, CrI3 monolayer. Our further investigation predicts that the Ca0.89δ0.11I2 system has a ferromagnetic ground state with Curie temperature of ∼238 K (XY model), which is considerably higher than the reported CrI3 monolayer (45 K). Further to this, such system has a high magnetic anisotropy energy (∼14.11 meV), which indicates that it can prohibit spin fluctuation. Therefore, we report here that alkaline earth metal halide based magnetic materials can be promising for next generation spintronics devices. © 2019 American Chemical Society.