Kondo effect and its destruction in hetero-bilayer transition metal dichalcogenides

Moiré superlattices, along with line-graph based d-electron systems, provide versatile platforms to realize flat bands. They open up the potential of a diverse correlation phase diagram, including the Kondo effect and its destruction [1,2]. Here, we assess such physics in AB-stacked hetero-bilayer transition metal dichalcogenide with tunable filling factor and perpendicular displacement field [2]. We study the fate of the heavy Fermi liquid state with tunable filling factor and perpendicular displacement field. Using a saddle point treatment, we identify a rich phase diagram that includes orbital-selective Mott phase and metallic phases with strong correlation induced orbital selectivity, when the displacement field and electron filling are tuned. We also argue that the qualitative behavior of the crossover associated with the picture of Kondo physics provides the understanding of the energy scales that have been observed in this system. From this understanding, we discuss the new regimes that these structures open up in the study of Kondo-destruction quantum criticality.

[1] H. Hu et al., arXiv:2210.14183. Q. Si et al., Nature 413, 804–808 (2001).

[2] W. Zhao et al, arXiv:2310.06044; Nature 616, 61 (2023).