Ahmet Avsar
EPFL
Defects are ubiquitous in solids and often introduce new properties that are absent in pristine materials especially at their low-dimensional limits [1]. For example, atomic-scale disorder in two-dimensional (2D) transition metal dichalcogenides is often accompanied by local magnetic moments, which can conceivably induce long-range magnetic ordering in these otherwise non-magnetic materials. In this talk, I will present magneto-transport properties of ultrathin PtSe2 crystals down to monolayer thickness and demonstrate the emergence of such extrinsic magnetism [2]. Electrical measurements supported by first-principles calculations and aberration-corrected transmission electron microscopy imaging of point defects show the existence of either ferromagnetic or anti-ferromagnetic ground state orderings depending on the number of layers in this ultra-thin material. By combining this defect-induced magnetism with unique thickness-dependent electronic properties of PtSe2 emerging from the strong coupling between layers [3], I will discuss its potential integration into several 2D spintronics device applications [4].
[1] D. Rhodes et al., Nat. Mater. 18, 541-549 (2019).[2] A. Avsar et al., Nat. Nanotechnol., 14, 674-678 (2019).
[3] A. Ciarrocchi, A. Avsar, D. Ovchinnikov and A. Kis, Nat Commun., 9, 919 (2018).
[4] A. Avsar et al., Rev. Mod. Phys., 92 (2), 021003 (2020).