NbS3: A unique quasi-one-dimensional conductor with three charge density wave transitions

We review the features of the charge density wave (CDW) conductor NbS3 (phase II) and include several additional results from transport, compositional, and structural studies. Particularly, we highlight three central results: (1) In addition to the previously reported CDW transitions at T-P1 = 360K and T-P2 = 150 K, a third CDW transition occurs at a much higher temperature T-P0 approximate to 620 - 650 K; evidence for the nonlinear conductivity of this CDW is presented. (2) We show that the CDW associated with the T-P2 transition arises from S vacancies acting as donors. Such a CDW transition has not been observed before. (3) We demonstrate the exceptional coherence of the T-P1 CDW at room temperature. The effects of uniaxial strain on the CDW transition temperature and transport are reported.