Thickness dependent charge density wave networks on thin 1T-TaS$_2$

Abstract: We investigate mechanically exfoliated thin 1T-TaS$_2$ with scanning tunneling microscopy at room temperature. Sample preparation without air exposure enables access to intrinsic charge-density-wave (CDW) phases of thin 1T-TaS$_2$. At room temperature, we can observe the expected nearly commensurate CDW (NCCDW) phase on thin flakes similar to bulk 1T-TaS$_2$. Further analysis reveals that the CDW domains in the NCCDW phase become smaller and have more anisotropic shape with decreasing thickness in the range of 8-28 layers. Our findings demonstrate that the anisotropic CDW nature of thin 1T-TaS$_2$ would be crucial to understand its exotic CDW-related phenomena and demand a systematic study on its correlation between the thickness-driven CDW domain anisotropy and the intermediate CDW states in thin 1T-TaS$_2$.