Proximity-Mediated Spin Transport Through Transition Metal Dichalcogenide Interfaces

Two-dimensional (2D) transition metal dichalcogenide (TMD) semiconductors are excellent van der Waals (vdW) material candidates for 2D optoelectronic applications. Owing to their excellent flexibility, it is possible to stack a 2D-TMD semiconductor (e.g., WS₂) with a magnetic material (e.g., Fe₃O₄) to create a novel heterostructure with an atomically sharp interface and properties that would otherwise be absent in their individual components. Here we report on the successful growth of WS₂/Fe₃O₄ films (WS₂thickness: 2 - 10 nm; Fe₃O₄thickness: 20 nm and 100 nm) using pulsed laser deposition and the enhanced magnetic and spin transport properties in these heterostructures by means of magnetometry, magnetic force microscopy, Anomalous Hall effect (AHE), and spin Seebeck effect (SSE). Fe₃O₄ films were grown on Si substrates, followed by deposition of WS₂ layer on the top of the Fe₃O₄ films. 5nm Pt layer was also deposited on the WS₂/Fe₃O₄ heterostructures for AHE and SSE measurements. We find that the incorporation of a thin WS₂ layer gives rise to the spin transport properties due to the interplay between the induced magnetism and electronic band structure close to the WS₂/Fe₃O₄ interface and highlight the important effects of magnetic proximity and charge transfer in 2D-TMD/ferromagnet systems for modern spintronics, opto-spintronics, valleytronics, and quantum communications.