Self-adaptive hetero-phase superlattices in TaS2 via layer-resolved 1T-to-1H transformations

Abstract Artificial hetero-phase superlattices constructed from transition metal dichalcogenides (TMDs) provide a powerful platform for exploring exotic physical phenomena and delivering structurally robust devices. However, achieving deterministic control over phase-stacking sequences in bulk architectures remains a significant challenge. Here, we report a self-adaptive superlattice system formed in TaS2 crystals through an in-situ structural phase transition. Coordinated inter-layer sliding and intra-layer S-plane sliding drive layer-resolved 1T-to-1H transformations. This two-dimensional (2D) transformation pathway enables deterministic and dynamic engineering of hetero-phase sequences within a three-dimensional (3D) crystal, with the resulting interfaces stabilized by persistent inter-phase coupling. Within these reconfigurable superlattices, we identify two distinct superconducting states arising from paired 1H/1T bilayers and sandwiched 1H/1T/1H’ trilayers. The charge density wave order remaining in the 1T layer suppresses superconductivity in the 1H/1T superlattice. Our findings establish an in-situ, sequence-controllable phase engineering strategy for constructing bulk TMD hetero-phase homostructures and highlight stacking configuration as a powerful degree of freedom for designing TMD-based quantum materials and devices.