Speaker
Description
Two-dimensional ($2$D) magnets have emerged as a promising platform for both fundamental studies of low-dimensional magnetism and the development of next-generation spintronic devices. However, intrinsic $2$D magnetic materials often suffer from low Curie temperatures, environmental instability, and limited tunability, posing significant challenges for practical device integration. To overcome these limitations, extrinsic dilute magnetic semiconductors (DMS) provide an alternative route to achieving robust magnetism in $2$D systems. In extrinsic DMS, a non-magnetic dopant interacts with a semiconducting host, inducing magnetic functionality without the need for intrinsic magnetic elements. This approach allows for precise control over atomic-scale interactions making them ideal platforms for investigating magnetic phenomena in $2$D materials. Here, we present the first realization of an extrinsic $2$D DMS in platinum-doped tungsten disulfide (Pt-WS$_2$). Using a bottom-up synthesis approach, we achieve a uniform and highly crystalline monolayer, where platinum selectively occupies the tungsten sub-lattice. The orbital hybridization between W $4d$ and Pt $5d$ orbitals leads to spin-selective states, resulting in a pronounced valley-Zeeman splitting. Our combined experimental and theoretical investigations reveal a sizable ferromagnetic response with a Curie temperature of approximately $375$ K. These findings demonstrate a novel strategy for engineering $2$D magnetism through atomic-level interaction design, paving the way for future advancements in spintronic devices, valleytronic applications, and magnetic nanoactuation.
Acknowledgements
This work was supported by the Taiwan National Science and Technology Council and Academia Sinica.
References
[1] Y. Chen et al., “Pt@WS2 ‐an Extrinsic 2D Dilute Ferromagnetic Semiconductor Beyond Room Temperature,” Small Methods, vol. 9, no. 3. Wiley, Sep. 20, 2024. https://doi.org/10.1002/smtd.202400955
