Dichalcogenides
Recent discoveries of superconductivity and charge density wave in two dimensional transition metal dichalcogenides (TMDs) have created lot of excitement in this class of materials. Electronic properties and therefore transport behavior in these materials depend on the anionic environment around metal ions. In 2H polytype, anions arrange in trigonal prismatic fashion whereas in 1T polytype the arrangement is octahedral. However there are other polytypes of TMDs are also known but those are less studied. Depending on the electron filling in d-orbitals, the certain type of structure can show semiconducting or metallic behavior. For example, 2H-NbSe2 and 1T-ReS2 are metallic (partially filled d orbitals) whereas 1T-HfS2, 2H-MoS2 and 1T-PtS2 are semiconductors because of fully occupied d orbitals. We prepare high quality single crystals of TMDs and study their transport behavior.
