Optical transparency in 2D ferromagnetic WSe 2 /1T-VSe 2 /WSe 2 multilayer with strain induced large anomalous Nernst conductivity

Transparent two-dimensional (2D) magnetic materials may bring intriguing features and are indispensable for transparent electronics. However, it is rare to find both optical transparency and room-temperature ferromagnetism simultaneously in a single 2D material. Herein, we explore the possibility of both these features in 2D WSe 2 /1T-VSe 2 (1ML)/WSe 2 and WSe 2 /1T-VSe 2 (2ML)/WSe 2 heterostructures by taking one monolayer (1ML) and two monolayers (2ML) of 1T-VSe 2 using first-principles calculations. Further, we investigate anomalous Hall conductivity (AHC) and anomalous Nernst conductivity (ANC) using a maximally localized Wannier function. The WSe 2 /1T-VSe 2 (1ML)/WSe 2 and WSe 2 /1T-VSe 2 (2ML)/WSe 2 systems show Curie temperatures of 328 and 405 K. Under biaxial compressive strain, the magnetic anisotropy of both systems is switched from in-plane to out-of-plane. We find a large AHC of 1.51 e 2 /h and 3.10 e 2 /h in the electron-doped region for strained WSe 2 /1T-VSe 2 (1ML)/WSe 2 and WSe 2 /1T-VSe 2 (2ML)/WSe 2 systems. Furthermore, we obtain a giant ANC of 3.94 AK −1 m −1 in a hole-doped strained WSe 2 /1T-VSe 2 (2ML)/WSe 2 system at 100 K. Both WSe 2 /1T-VSe 2 (1ML)/WSe 2 and WSe 2 /1T-VSe 2 (2ML)/WSe 2 are optically transparent in the visible ranges with large refractive indices of 3.2–3.4. Our results may suggest that the WSe 2 /1T-VSe 2 /WSe 2 structure possesses multifunctional physical properties and these features can be utilized for spintronics and optoelectronics device applications such as magnetic sensors, memory devices, and transparent magneto-optic devices at room temperature.