|Description||2018 Fall Physics Colloquium Series|
Shao-Chun Li, Ph.D.
Professor of Physics
National Laboratory of Solid State Microstructures
School of Physics
Nanjing University Collaborative Innovation Center of Advanced Microstructures
Growth and Characterization of single-layer 1T’-WTe2
The discovery of topological insulators (TIs) has drawn intense attention due to the intriguing properties of this new type of quantum matter. Single-layer 1T’- WTe2 has been recently predicted as the candidate of quantum spin Hall material. Even though experimental progress has been made, the band structure of 1T’-WTe2 is still not well determined. In this presentation, we systematically discuss the growth and characterization of 1T’-WTe2 film. By using the epitaxial graphene /SiC(0001) as the substrate, we found 1T’-WTe2 initially prefers the single-layer growth mode, followed by the nucleation of the second layer on top of the first layer. Scanning tunneling microscopy was applied to investigate the electronic structure of single-layer 1T’-WTe2 as well as its topological edge states. In contrast to the ARPES results, we find the 1T’-WTe2 holds a semimetal-like band structure and the existence of Coulomb gap at the Fermi energy. The Coulomb gap efficiently suppresses the bulk state with the edge state unchanged, thus facilitating the observation of quantum spin Hall effect in this system.
1. Z. Jia, et al., “Direct visualization of a two-dimensional topological insulator in the single-layer 1T’-WTe2” Phys. Rev. B 96, 041108(R) (2017).
2. Y. Song et al., “Observation of Coulomb gap in the quantum spin Hall candidate single-layer 1T’-WTe2” arXiv:1711.07286
For more information contact: Dr. Anzhong Wang 254-710-2276