Monolayer 1T-TaS₂ is a Mott insulator in which electron correlations create a triangular lattice of local magnetic moments, whereas in bulk crystals its insulating gap comes from coupling between layers. QMAT researchers at Aalto University exploit this stacking dependence to show that twisted 1T-TaS₂ bilayers form mosaic superlattices.

In these mosaics, regions with local magnetic moments alternate with non-magnetic insulating regions, following the moiré pattern. An interlayer bias can tune the mosaic, transferring charge between layers and quenching the correlations. The work establishes twisted 1T-TaS₂ as a flexible platform for engineering spatially modulated correlated phases. The authors are Ana Vera Montoto, Jose Lado and Adolfo Fumega of the Correlated Quantum Materials group.

Figure: Vera Montoto et al., Nano Lett. (2026); image from arXiv:2604.02001, CC BY 4.0