Sliding state of the quasi-two dimensional CDW system TbTe3 probed by coherent x-ray diffraction

Coherent x-ray diffraction experiments have been performed to probe the sliding state of a quasi-two dimensional charge density wave (CDW) in TbTe3. The 2kF satellite reflection associated with the CDW has been observed with respect to external dc currents, on both sides of the threshold current. These measurements illustrate how the periodic lattice distortion associated to the CDW supports the collective motion of a sliding CDW in a quasi-two dimensional system. A comparison with the quasi-one dimensional NbSe3 system is done.