Scanning Nearfield Optical Microscopy study of 1T-TaS₂

1T-TaS₂ is a transition metal dichalcogenide (TMD) with several notable features. Upon cooling, it undergoes several phase transitions to a non-commensurate charge-density-wave (CDW) state and further to a commensurate charge-density wave state. In this commensurate CDW ground state where the Ta atoms form star-of-David clusters, 1T-TaS₂ is said to be in a Mott insulating state. Furthermore, 1T-TaS₂ has been proposed to be a spin liquid candidate in this CDW ground state. In this talk, I will present data taken using scattering type scattering type scanning near-field optical microscopy (s-SNOM) on a graphene encapsulated thin flake of 1T-TaS₂, where we have imaged the near-field optical response through the metal-insulator transition down to a temperature of 50K.