Interplay of Substrate Interactions and Strain in the Emergent Magnetism of Pd Thin Films on MoS₂(0001)

Pd adlayers on 2H-MoS₂(0001) are commensurate with the substrate and adopt the 3.16 Å lattice constant of the 2H-MoS₂(0001) substrate [1]. This in-plane Pd-Pd spacing is vastly expanded from the natural Pd-Pd spacing of 2.75 Å and thus makes this system ideal for investigating the effects of strain and substrate on the magnetic behavior of palladium (Pd) thin films using density functional theory (DFT). While unstrained Pd(111) thin films remain non-magnetic up to three layers [2], the 15% lattice expansion seen for Pd bilayers on 2H-MoS₂(0001) is associated with magnetism leading to small moments of 0.327 and 0.42 μ_B/Pd atom for the first and second Pd layer respective. Magnetization is quenched in monolayer Pd on 2H-MoS₂(0001) because of strong hybridization and charge transfer across the interface. Our calculations show that spin–orbit coupling is associated with magnetic reorientation in the Pd films. These results demonstrate the critical influence of strain and interface effects in tuning magnetism in Pd-based adlayers.

[1] W. K. Chin, T. Komesu, B. Ashraf, Y. Kumar, Y. Miyai, A. Kumar, D. Le, E. F. Schwier, S. Ideta, T. S. Rahman, K.Shimada, and P. A. Dowben, "Commensurate palladium adlayer formation on 2H−MoS₂(0001)", J. Phys. Chem. C 129 (2025) 15003−15009; doi: 10.1021/acs.jpcc.5c02908

[2] T. H. Ho, S. H. Rhim, and S. C. Hong, “Role of quantum well in Pd(111) thin film magnetism,” Journal of Magnetism and Magnetic Materials, 563(2022) 169891; doi: 10.1016/j.jmmm.2022.169891.