biostudies-literatureCrippa LEuropean Research Council1357https://www.ebi.ac.uk/biostudies/studies/S-EPMC10866876biostudies-literatureUnknown15(1)Controlling and understanding electron correlations in quantum matter is one of the most challenging tasks in materials engineering. In the past years a plethora of new puzzling correlated states have been found by carefully stacking and twisting two-dimensional van der Waals materials of different kind. Unique to these stacked structures is the emergence of correlated phases not foreseeable from the single layers alone. In Ta-dichalcogenide heterostructures made of a good metallic "1H"- and a Mott insulating "1T"-layer, recent reports have evidenced a cross-breed itinerant and localized nature of the electronic excitations, similar to what is typically found in heavy fermion systems. Here, we put forward a new interpretation based on first-principles calculations which indicates a sizeablNature communicationsHeavy fermions vs doped Mott physics in heterogeneous Ta-dichalcogenide bilayers.PMC10866876815869Bae HCrippa LWehling TMazin IIYan BWunderlich PSangiovanni GValenti RfalseHeavy fermions vs doped Mott physics in heterogeneous Ta-dichalcogenide bilayers.Controlling and understanding electron correlations in quantum matter is one of the most challenging tasks in materials engineering. In the past years a plethora of new puzzling correlated states have been found by carefully stacking and twisting two-dimensional van der Waals materials of different kind. Unique to these stacked structures is the emergence of correlated phases not foreseeable from the single layers alone. In Ta-dichalcogenide heterostructures made of a good metallic "1H"- and a Mott insulating "1T"-layer, recent reports have evidenced a cross-breed itinerant and localized nature of the electronic excitations, similar to what is typically found in heavy fermion systems. Here, we put forward a new interpretation based on first-principles calculations which indicates a sizeabl2024-01-01T00:00:00Z2024 Feb2025-04-22T22:01:48.605Z2025-04-06T03:54:03.286ZS-EPMC108668763835569410.1038/s41467-024-45392-y