Fig. 2: Endotaxial polytype heterostructure of TaS2.
From: Endotaxial stabilization of 2D charge density waves with long-range order
a In bulk TaS2, an IC-CDW phase emerges above 350 K, with azimuthally diffused superlattice peaks characteristic of hexatic disorder. b oIC-CDW in endotaxial polytype heterostructure has enhanced long-range order and amplitude. Superlattice peaks are well-defined, sharper and brighter. c Evolution of IC-CDW during the endotaxial synthesis. Atomic resolution cross-sectional HAADF-STEM of (d) bulk and (e) heat-treated TaSxSe2-x confirms polytypic transformation. After treatment, Pr layers encapsulate monolayers of Oc layers. Scale bar is 2 nm. A selenium-doped sample was imaged to enhance chalcogen visibility. f Resistivity vs. temperature measurement of bulk (brown) and thermally-treated (red) TaS2 shows an increase in resistivity. In pristine sample, IC-CDW gives way to nearly commensurate (NC-) CDW around 350 K. In polytype heterostructure, twinned commensurate (tC-) CDW emerges at a similar temperature range.
