Transition metal dichalcogenides

TMDs are quasi-two-dimensional systems characterized by strong in-plane bonding and weak inter-layer coupling. This weak interlayer coupling enables exfoliation to single layer form, which in combination with direct band-gap, strong spin-orbit coupling and favorable electronic and mechanical properties makes them interesting for fundamental studies as well as for various applications. Also in the bulk form, their reduced dimensionality makes TMD’s susceptible to collective electronic instabilities such as superconductivity and charge density waves (CDW). Weak van der Waals interlayer coupling enables intercalation of TMD’s by various atoms and molecules.

Especially interesting is intercalation with magnetic atoms because it connects TMD’s to the wider field of research on the interplay between conducting electrons and magnetic lattice degrees of freedom. The particular advantage of TMD’s in this field lies in the possibility to combine various metallic layers with various magnetic intercalants, and in the attractive opportunity to fine-tune the coupling between two subsystems by relatively modest hydrostatic pressure. Finally, magnetically intercalated TMDs are known to develop various magnetic phases, witnessing the competition of magnetic couplings of different signs, ranges, and physical origins. Recently theoretically proposed topological effects in electronic band structure of parent and intercalated systems makes investigation of those materials even more interesting in the light of possible applications. All those properties interpolate them between heavy fermion compounds, high-temperature superconductors and topological materials.

We focus on several aspects of intercalated TMDs: first are magnetic interactions that are relatively long ranged (at least third nearest neighbors are necessary to consider when modeling their ground states) and their interaction with metallic degrees of freedom. Second is effect of disorder on ground states of (intercalated) TMDs. Third is effect of uniaxial and hydrostatic pressure on ground states and finally, topological aspects of TMDs.