Magnetism in 2-dimensional van der Waals materials attracts lots of research attention, and simultaneously, poses a challenge to the capability of our state-of-the-art measurement/simulation techniques. Here in this talk, I will try to present a brief overview of how first-principles-based theoretical methods can elucidate this intriguing material class when the experimental information is limited. By combining several different levels of approximations with the advacned magnetic force response theory, we try to understand the van der Waals superexchange (or, ‘super-super’ exchange), the role of defects, and other magnetic properties. The materials that we previously studied include Mott insulating CrI₃ [1], metallic Fe₃GeTe₂ [2], and two different transition-metal dichalcogenides [3, 4]. I will also try to outline the remaining open problems.

[1] S. W. Jang et al., Phys. Rev. Mater. 3 031001 (R) (2019).

[2] S. W. Jang et al., arXiv:1904.04510 (submitted).

[3] T. J. Kim et al., arXiv:1907.04790 (submitted).

[4] D. Won, D. H. Kiem et al., Adv. Mater (in press).

Host: Prof. Je-Geun Park