Sliding-Induced Decoupling and Charge Transfer between the Coexisting Q1 and Q2 Charge Density Waves in NbSe3

International audience; Using high-resolution x-ray scattering in the presence of an applied current, we report evidence for a dynamical decoupling between the two NbSe3 charge-density waves (CDWs), Q1 (TC1 = 145 K) and Q2 (TC2 = 59 K), coexisting below TC2. Simultaneous and oppositely directed shifts of the relevant CDW superlattice spots develop above a threshold current which we identify as the depinning threshold IC1 for the more strongly pinned upper CDW Q1 (IC1~10IC2). In contrast with shifts induced by current conversion processes, the present effect is not current polarized and is not limited to the current-contact regions. We propose a model which explains this instability through a sliding-induced charge transfer between the two electronic reservoirs corresponding to the Q1 and Q2 CDWs.