Atomic-scale insights into a quasi-1D CDW system by scanning tunneling microscopy and in situ electronic transport

Many low-dimensional quantum materials exhibit intriguing electronic instabilities which lead to the formation of charge density wave (CDW), a symmetry-broken microscopic phase accompanied by a novel periodic electronic arrangement. Remarkably, these systems manifest non-linear current-voltage (I-V) characteristics, featuring dynamic CDW sliding beyond a specific threshold voltage. However, to date, atomic-scale evidence detailing the nature of CDW sliding and pinning is lacking. Here, we combine scanning tunneling microscopy and spectroscopy (STM/STS) with in situ electronic transport measurements, enabling us to investigate the CDW sliding dynamics in potassium blue bronze (K0.3MoO3), a prototypical quasi-1D material that hosts a CDW phase transition near 180K. Temperature-dependent STM measurements provide highly-resolved atomic-scale images of the potassium blue bronze CDW phase, including a possible novel surface reconstruction and/or termination. In situ transport measurements at finite source-drain threshold voltage reveal clear signs of CDW sliding. Finally, atomic-scale evidence of CDW sliding via tunneling current noise mapping will be discussed.