Interlayer Coupling Driven Correlated and Charge-Ordered Electronic States in a Transition Metal Dichalcogenide Superlattice

Yiwei Li; Lixuan Xu; Shihao Zhang; Lanxin Liu; Yifan Zhou; Qiang Wan; Shiwei Chen; Shiheng Liang; Yulin Chen; Yi-feng Yang; Xuan Luo; Yuping Sun; Nan Xu; Zhongkai Liu

doi:10.1016/j.newton.2026.100530.

arXiv · 2511.14570

Interlayer Coupling Driven Correlated and Charge-Ordered Electronic States in a Transition Metal Dichalcogenide Superlattice

Yiwei Li·Lixuan Xu·Shihao Zhang·Lanxin Liu·Yifan Zhou·Qiang Wan·Shiwei Chen·Shiheng Liang·Yulin Chen·Yi-feng Yang·Xuan Luo·Yuping Sun·Nan Xu·Zhongkai Liu

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Abstract

4Hb-TaS_2, a van der Waals superlattice comprising alternate stacked Ising superconducting 1H-TaS_2 and cluster Mott insulating 1T-TaS_2, exhibits emergent properties beyond those of its constituent layers. Notable phenomena include time-reversal-symmetry-breaking superconductivity and spontaneous vortex phases, which are driven by nontrivial interlayer interactions that remain debated. Using area-selective angle-resolved photoemission spectroscopy, we provide direct spectroscopic evidence of such interaction by systematically probing the electronic structures of 1T- and 1H-terminted surfaces of 4Hb-TaS_2. The metallic states of subsurface 1H-layers are folded to the Brillouin zone center by the sqrt(13) by sqrt(13) modulation of the surface 1T-layer, forming chiral "windmill" Fermi surfaces via Umklapp scattering. These conducting states further hybridize with the incipient flat band of the surface 1T-layer, producing a Kondo-like peak at the Fermi level. Interlayer charge transfer induces distinct 3 by 3 and 2 by 2 charge orders on the surface and subsurface 1H-layers, respectively, which result in characteristic segmented Fermi surfaces and dichotomously shift the van Hove singularities. These findings reconcile the competing Kondo and Mott-Hubbard models in this material and emphasize the interplay of flat bands, van hove singularities, charge orders, and unconventional superconductivity in correlated superlattices.

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Yiwei Li, Lixuan Xu, Shihao Zhang, Lanxin Liu, Yifan Zhou, Qiang Wan, Shiwei Chen, Shiheng Liang, Yulin Chen, Yi-feng Yang, Xuan Luo, Yuping Sun, Nan Xu, Zhongkai Liu. 2025-11-18. Interlayer Coupling Driven Correlated and Charge-Ordered Electronic States in a Transition Metal Dichalcogenide Superlattice. https://doi.org/10.1016/j.newton.2026.100530.

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