Review of nanoscale layered transition metal chalcogenide superconductors

Here we summarized the nanoscale layered transition metal chalcogenide superconductors, mainly based on the experimental results. In transition-metal chalcogenides the interplay between strong electron-electron and electron-phonon interactions produces a wide variety of instability ranging from charge density wave to superconducting state. The majority of bulk transition-metal dichalcogenides Tcs are normally between 2 and 4 K. At present, superconducting transition-metal chalcogenides generally show low transition temperature (Tc < 10 K). Fe based transition-metal chalcogenides have certain higher Tc (in the range of 10 ~ 50 K). As have been reported, nano-transition-metal chalcogenides may be one of the routes to improve the superconducting transition temperature. In this review, we would like to give a brief introduction of superconductor development and crystal structure of transition-metal chalcogenides. Furthermore, we will describe major synthesis and physical properties of nano