Chiral Nature of the Nearly-Commensurate Charge Density Wave State in 1T-TaS₂

1T-TaS₂ is a well-studied compound which plays host to a wealth of interesting physics.  Prominent in the material are four charge density wave (CDW) phases – commensurate, triclinic, nearly-commensurate, and incommensurate.  Here we present our room-temperature scanning tunneling microscopy studies of the nearly-commensurate (NC) CDW state.  The NC-CDW state involves hexagonally ordered domains.  Within a domain, the CDW spacing resembles that of the low-temperature commensurate CDW state, and domains are separated by an incommensurate CDW domain-wall network.  In our studies, we refine this characterization and show that, within a domain, the CDW state is not locked-in to the commensurate state but rather there is a continual evolution of the CDW state from domain wall to domain center.  Further, we find evidence for an intradomain CDW chirality driven by a strong coupling of the CDW to the lattice.