Lattice-Driven Chiral Charge Density Wave State in 1T-TaS${}_2$

Abstract

We use scanning tunneling microscopy to study the domain structure of the nearly-commensurate charge density wave (NC-CDW) state of 1T-TaS${}_2$. In our sub-angstrom characterization of the state, we find a continual evolution of the CDW lattice from domain wall to domain center, instead of a fixed CDW arrangement within a domain. Further, we uncover an intradomain chirality characterizing the NC-CDW state. Unlike the orbital-driven chirality previously observed in related transition metal dichalcogenides, the chiral nature of the NC-CDW state in 1T-TaS${}_2$ appears driven by a strong coupling of the NC-CDW state to the lattice.