Observation of dynamic coupling between the Q1 and Q2 charge-density waves in NbSe3 -: art. no. 041103

We report synchrotron based high-resolution x-ray scattering and in situ electronic transport measurements of the Q(1) and Q(2) charge-density waves (CDW's) in NbSe3 as a function of applied electric field in the low-temperature "switching" regime. Derailed analysis of the line shape of the x-ray satellite peaks demonstrates that the Q(2) CDW changes state when it depins at E-T but does not exhibit any abrupt structural change at E-T*. where the collective CDW current abruptly increases. In contrast, the el CDW does not exhibit structural changes at E-T but abruptly changes state at E-T* to a structure very similar to the structure of the sliding el at high temperatures. These data demonstrate coupling between the Q(2) and Q(1) CDW's.