Sliding Charge Density Waves (CDW) systems under applied current probed by X-Ray Free Electron Laser

As soon as current is applied to a CDW system, the CDW deforms due to pinning at surfaces [1,2], and beyond a threshold current the Ohm’s law is not fulfilled anymore because of an extra current appearing in the crystal. This phenomenon is called sliding CDW and it is what we want to investigate in this study. The additional current could be based on moving CDW solitons travelling across the sample. These topological objects correspond to 2π phase shifts of the CDW modulation, making regular lattice with very large period up to micrometers, as theoretically described and experimentally observed [3,4].