Observation of Non-Hexagonal Domains in the Nearly-Commensurate CDW State of 1T-TaS2

The quasi-two-dimensional 1T-TaS2 is an intriguing material which hosts four distinct charge density wave (CDW) states and whose electronic properties can be manipulated or perturbed through a variety of methods including temperature, pressure, sample thickness variations, and the application of optical and voltage pulses. At low temperatures, 1T-TaS2 is in a commensurate CDW state. External perturbations, such as application of local voltage pulses or optical pulses, have led to non-hexagonal domaining and to new electronic orders emerging from within this commensurate CDW state. In this talk, we present our scanning tunneling microscopy measurements of the higher-temperature nearly-commensurate (NC) CDW state. We report observation of non-hexagonal domains in addition to the typical hexagonally-organized domains within the NC-CDW state. We compare the non-hexagonal domains observed in the NC-CDW state to those previously observed in the perturbed C-CDW state.