Spin-polarized conductivity and spin-dependent Seebeck effect in magnetized graphene

Graphene-based van der Waals heterostructures have shown to be an excellent choice for two-dimensional (2D) spintronic devices as the superior spin and charge transport properties of graphene are enriched via the proximity to other 2D materials. By the proximity effects, one can induce spin-orbit and magnetic exchange interactions in the graphene which provide strong coupling between charge and spin currents [1-4]. In particular, our recent spin transport measurements in graphene in the proximity of a 2D interlayer antiferromagnet, Chromium Sulfide Bromide (CrSBr) have shown strong spin polarization of conductivity in graphene (∼14%) that arises from a large induced exchange interaction. The strong spin-polarization of conductivity also results in the observation of the spin-dependent Seebeck effect in graphene. This is the first-time experimental realization of the active role of the magnetic graphene in the electrical and thermal generation of spin currents, addressing the most technologically relevant aspects of the magnetism in graphene. Also, the high sensitivity of the spin-transport in graphene to the magnetization of the outer-most layer of the CrSBr provides the tool to read out a single magnetic sublattice. The spin-polarization of conductivity and spin-dependent Seebeck coefficient in magnetic graphene, together with its exceptional long-distance spin transport suggest a magnetic graphene as an ultimate building block for ultra-compact magnetic memory and sensory devices and provide substantial advances in 2D spintronic and caloritronic systems [4].

[1] Ghiasi, T.S., et al., Nano letters 17.12 (2017): 7528-7532.
[2] Ghiasi, T.S., et al., Nano letters 19.9 (2019): 5959-5966.
[3] Avsar, A., et al., Reviews of Modern Physics 92.2 (2020): 021003.
[4] Ghiasi, T.S., et al., arXiv:2007.15597 (2020), submitted to Nature Nano.