Tailoring and probing the quantum states of matter of 2D Dirac materials with a buckled honeycomb structure

Z. Jiao, Q. Yao, H. J.W. Zandvliet*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

The quantum state of matter of a two-dimensional Dirac material with a buckled honeycomb structure can be tuned by an electric field. In the absence of an external electric field the material is a topological insulator owing to the spin-orbit coupling, which opens a band gap at the K and K points of the Brillouin zone. The size of this band gap decreases with increasing electric field until eventually the band gap completely closes at a critical electric field Ec and the material becomes a semi-metal. For electric fields exceeding Ec the band gaps reopens again and the material undergoes a topological phase transition from a semi-metal to a normal band insulator. The electric field in a tunnel junction depends on the applied voltage bias across the junction as well as the difference in work function of the two electrodes. Here we show how scanning tunneling microscopy can be employed to simultaneously apply an electric field and study the electronic structure of a two-dimensional Dirac material with a buckled honeycomb structure. The electric field applied by the scanning tunneling microscope offers the possibility to locally alter the quantum state of matter of two-dimensional topological insulator to a semi-metal or normal band insulator. This results in the development of topologically protected spin polarized edge states within the material. We present a spectroscopic method to probe these topologically protected edge states.

Original languageEnglish
Article number114113
JournalPhysica E: Low-Dimensional Systems and Nanostructures
Volume121
DOIs
Publication statusPublished - Jul 2020

Keywords

  • UT-Hybrid-D

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