- Jan Honolka: Magnetic order in 2D systems: example of RKKY-coupled Co spins on WS2 monolayers
- 21.10. 2020, 14:10
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Abstract:
Magnetic order can break fundamental symmetries in 2D materials, which affects potential spintronic, optoelectronic and superconducting properties [1, 2]. Here, I will summarize our recent research on structural and electronic properties of various transition metal chalcogenide (TMC) materials and the implementation of magnetic degrees of freedom. As an example, I will focus on magnetic and structural properties of cold-deposited Co atoms on single layer WS2/Au(111), which are characterised by x-ray magnetic circular dichroism (XMCD) measurements and scanning tunneling microscopy (STM) and spectroscopy (STS). We observe a highly compensated magnetic state at intermediate Co coverages of 0.2 - 0.3 monolayers. Density functional theory shows that indirect RKKY coupling constants between Co adatoms are of the order of few meV and negative at Co-Co distances 0.5 - 1 nm, which creates a non-collinear magnetic structure. In the limit of 1 monolayer ferromagnetism sets in. Strain effects due to the substrate are discussed.
[1] Kenneth S. Burch, David Mandrus & Je-Geun Park, Nature 563, 47-52 (2018)
[2] Xiao et al., PNAS 110, 3738-3742 (2013)