Imaging twisted bilayer 1T’-WTe₂ with scanning tunneling microscopy and spectroscopy

Moiré patterns in two-dimensional materials arise from interference between lattices with a small lattice-constant mismatch or a slight rotational misalignment, offering means to engineer emergent structural and electronic phenomena. Twisted bilayer 1T’-WTe₂ (tWTe₂) is a notable example. In monolayer form, WTe₂ is a candidate topological excitonic insulator at charge neutrality and becomes superconducting upon electron doping. When two layers are twisted slightly away from the natural bilayer stacking, tWTe₂ is expected to form a rectangular moiré pattern. This texture hosts domains of alternating out-of-plane ferroelectric polarization separated by one-dimensional solitonic domain walls, with potential connections to coupled-wire Luttinger liquid models. Despite these prospects, experimental studies of tWTe₂ remain limited, in part due to fabrication challenges. Here, we report scanning tunneling microscopy and spectroscopy (STM/S) of small-angle tWTe2, enabled by recent advances in device assembly. We identify solitonic domain walls in STM topography and investigate their structural and electronic properties under electrostatic gating. Our results establish tWTe2 as a promising platform for one-dimensional physics, and open a path to systematic twist-angle-dependent studies.