Scanning tunnelling microscopy study of the charge-density wave inHf-doped 1T-TaS2

Abstract

The effect of doping with Hf atoms on the nearly commensurate (NC)charge-density-wave (CDW) structures of 1T-TaS2 wasinvestigated using scanning tunnelling microscopy (STM) at roomtemperature, for levels of substitution of Hf for Ta up to 6.9%.It was found that the Hf atom introduces a point defect to the CDWsuperlattice at the CDW domain boundary for lower contents. For Hfcontents higher than 1%, the CDW superlattice melted and adistorted structure was observed instead of the usual CDWsuperlattice. The change of the CDW structure observed by STM wascompared with the change of the ρ-T characteristics.