Strong charge density wave fluctuation and sliding state in PdTeI with quasi-one-dimensional PdTe chains

In quasi-one-dimensional (quasi-1D) systems, because of the finite interchain coupling and fluctuation, the charge density wave (CDW) transition temperature TCDW is much lower than the mean-field-theory predicted TMF and the CDW fluctuation region exists between TCDW and TMF. Usually, CDW fluctuation has little effect on the electronic transport properties. Moreover, the CDW state is usually insensitive to magnetic field. The work done here on a PdTeI single crystal with quasi-1D PdTe chains shows that the above statements need to be revisited. It is found that the CDW fluctuation leads to a gradual decrease of carrier concentration before the static long-range CDW order occurs at T₁~110 K. On the other hand, the pinning and sliding of CDW state are observed below T₂~6 K. When such a low T₂ is combined with the existence of multiple quasi-1D bands, PdTeI exhibits exotic crossover behavior from negative to huge positive magnetoresistance under magnetic field and field-induced localization. It indicates that the CDW fluctuation could have a remarkable influence on transport properties of CDW materials. Moreover, there is an interaction between the CDW state and magnetic field.