Optical transparency in 2D ferromagnetic WSe2/1T-VSe2/WSe2 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 WSe₂/1T-VSe₂ (1ML)/WSe₂ and WSe₂/1T-VSe₂ (2ML)/WSe₂ heterostructures by taking one monolayer (1ML) and two monolayers (2ML) of 1T-VSe₂ using first-principles calculations. Further, we investigate anomalous Hall conductivity (AHC) and anomalous Nernst conductivity (ANC) using a maximally localized Wannier function. The WSe₂/1T-VSe₂ (1ML)/WSe₂ and WSe₂/1T-VSe₂ (2ML)/WSe₂ 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 e²/h and 3.10 e²/h in the electron-doped region for strained WSe₂/1T-VSe₂ (1ML)/WSe₂ and WSe₂/1T-VSe₂ (2ML)/WSe₂ systems. Furthermore, we obtain a giant ANC of 3.94 AK⁻¹ m⁻¹ in a hole-doped strained WSe₂/1T-VSe₂ (2ML)/WSe₂ system at 100 K. Both WSe₂/1T-VSe₂ (1ML)/WSe₂ and WSe₂/1T-VSe₂ (2ML)/WSe₂ are optically transparent in the visible ranges with large refractive indices of 3.2–3.4. Our results may suggest that the WSe₂/1T-VSe₂/WSe₂ 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. [ABSTRACT FROM AUTHOR]