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

Binbin Wang; Wei Xia; Si Li; Kang Wang; Shengyuan A Yang; Yanfeng Guo; Jiamin Xue

doi:10.1021/acsnano.1c00320

One-Dimensional Metal Embedded in Two-Dimensional Semiconductor in Nb₂Si_x-1Te₄

ACS Nano. 2021 Apr 27;15(4):7149-7154. doi: 10.1021/acsnano.1c00320. Epub 2021 Mar 19.

Authors

Binbin Wang^{1

2}, Wei Xia^{1

3}, Si Li^{4

5}, Kang Wang^{1

2}, Shengyuan A Yang⁴, Yanfeng Guo¹, Jiamin Xue¹

Affiliations

¹ School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China.
² University of Chinese Academy of Sciences, Beijing 100049, China.
³ ShanghaiTech Laboratory for Topological Physics, Shanghai 201210, China.
⁴ Research Laboratory for Quantum Materials, Singapore University of Technology and Design, Singapore 487372, Singapore.
⁵ School of Physics, Northwest University, Xi'an 710069, China.

PMID: 33739831
DOI: 10.1021/acsnano.1c00320

Abstract

The ternary van der Waals material Nb₂Si_x-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 Nb₂Si_x-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.

Keywords: 1D metallic chain; 2D semiconductor; Nb2Six−1Te4; anisotropy; scanning tunneling microscopy (STM); standing waves.