Metal-insulator transition in two-dimensional transition metal dichalcogenides

The emergence of layered transition metal dichalcogenides has invigorated interests in the challenging problem of metal-insulator transition in two dimensions. The observed clearly distinctive conductivity dependences on temperature show diverse characteristic features of metal-insulator transition depending on the material thickness from which the relative strength of disorder and carrier-carrier interactions can be modulated. These various properties provoked several different proposals for the responsible transition mechanism, providing ideal testing grounds for the study of two-dimensional metal-insulator transition. In this article, we overview the current progresses and challenging issues in the study of metal-insulator transition in two-dimensional layered transition metal dichalcogenides.