One-Dimensional Metal Embedded in Two-Dimensional Semiconductor in Nb2Six–1Te4

Authors:

Abstract
The ternary van der Waals material Nb2Six–1Te4 demonstrates many interesting properties as the content of Si is changed, ranging from metallic Nb3SiTe6 (x = 5/3) to narrow-gap semiconductor Nb2SiTe4 (x = 2) and with the emergence of one-dimensional Dirac fermion excitations in between. An in-depth understanding of their properties with different stoichiometry is important. Here we use scanning tunneling microscopy and spectroscopy to reveal that Nb2Six–1Te4 is a system with spontaneously developed and self-aligned one-dimensional metallic chains embedded in a two-dimensional semiconductor. Electron quasiparticles form one- and two-dimensional standing waves side by side. This special microscopic structure results in strong transport anisotropy. Along the chain direction the material behaves like a metal, while perpendicular to the chain direction, it behaves like a semiconductor. These findings provide an important basis for further investigation of this intriguing system.
Funding Information
  • Ministry of Science and Technology of the People's Republic of China (2017YFA0305400)
  • Ministry of Education - Singapore (MOE2019-T2-1-001)
  • ShanghaiTech University
  • National Natural Science Foundation of China (11874264)
  • Chinese Academy of Sciences (XDA18010000)

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