Evidence of striped electronic phases in a structurally modulated superlattice.

Abstract

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 interesting¹, 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 SrTa₂S₅ realizing an incommensurate one-dimensional (1D) structural modulation of 2D transition metal dichalcogenide (TMD) H-TaS₂ layers. High-quality electronic transport in the H-TaS₂ 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 SrTa₂S₅ 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 SrTa₂S₅ is spatially modulated and mismatched between adjacent TMD layers. With phenomenology suggestive of pair-density wave superconductivity^15-17, SrTa₂S₅ may present a pathway for microscopic evaluation of this unconventional order^18-21. More broadly, SrTa₂S₅ 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.