Evidence of striped electronic phases in a structurally modulated superlattice.

The electronic properties of crystals can be manipulated by superimposing spatially periodic electric, magnetic or structural modulations. Long-wavelength modulations incommensurate with the atomic lattice are particularly interesting 1 , exemplified by recent advances in two-dimensional (2D) moiré materials 2,3 . Bulk van der Waals (vdW) superlattices 4-8 hosting 2D interfaces between minimally disordered layers represent scalable bulk analogues of artificial vdW heterostructures and present a complementary venue to explore incommensurately modulated 2D states. Here we report the bulk vdW superlattice SrTa 2 S 5 realizing an incommensurate one-dimensional (1D) structural modulation of 2D transition metal dichalcogenide (TMD) H-TaS 2 layers. High-quality electronic transport in the H-TaS 2 layers, evidenced by quantum oscillations, is made anisotropic by the modulation and exhibits commensurability oscillations paralleling lithographically modulated 2D systems 9-11 . We also find unconventional, clean-limit superconductivity in SrTa 2 S 5 with a pronounced suppression of interlayer relative to intralayer coherence. The in-plane magnetic field dependence of interlayer critical current, together with electron diffraction from the structural modulation, suggests superconductivity 12-14 in SrTa 2 S 5 is spatially modulated and mismatched between adjacent TMD layers. With phenomenology suggestive of pair-density wave superconductivity 15-17 , SrTa 2 S 5 may present a pathway for microscopic evaluation of this unconventional order 18-21 . More broadly, SrTa 2 S 5 establishes bulk vdW superlattices as versatile platforms to address long-standing predictions surrounding modulated electronic phases in the form of nanoscale vdW devices 12,13 to macroscopic crystals 22,23 .