Transverse conductivity in the sliding CDW state of NbSe_3
  The dynamical properties of longitudinal and transverse conduction of NbSe$_3$ single-crystals have been simultaneously studied when the current is applied along the b axis (chain direction). In the vicinity of the threshold electric field for CDW sliding, the transverse conduction sharply decreases. When a rf field is applied, voltage Shapiro steps for longitudinal transport are observed as usual, but also current Shapiro steps in the transverse direction. The possible mechanisms of this effect are discussed. 
A. A. Sinchenko, P. Monceau and T. Crozes
cond-mat.str-el