Stacking-Dependent Electronic States in the Natural van der Waals Heterostructure 4Hb-TaS_2-xSex

Natural van der Waals (vdW) materials offer a fertile ground for exploring stacking-dependent physics analogous to moiré superlattices. In this study, we investigate lightly Se-doped 4Hb-TaS₂ single crystals, which consist of alternating 1T and 1H layers. Two types of crystals, S1 and S2, synthesized under identical growth conditions, exhibit distinct crystalline structures and electronic states. While both retain the 4Hb framework, S2 possesses a relative in-plane stacking shift between adjacent layers compared to S1. This structural modification enhances the star-of-David charge-density-wave (CDW) transition temperature from 315 K in S1 to 327 K in S2 and alters the interlayer CDW registry. Crucially, S2 displays a rare nonlinear Hall response featuring two plateau-like characteristics, starkly contrasting with the behavior observed in S1. A phenomenological multiband analysis suggests that these plateau-like characteristics may be qualitatively associated with electron–hole compensation in the transport response. Our findings establish interlayer stacking as a potent tuning parameter for manipulating emergent electronic states in natural vdW systems.