Electric-field-tuned topological phase transition in ultrathin Na3Bi

James L. Collins, Anton Tadich, Weikang Wu, Lidia C. Gomes, Joao N. B. Rodrigues, Chang Liu, Jack Hellerstedt, Hyejin Ryu, Shujie Tang, Sung-Kwan Mo, Shaffique Adam, Shengyuan A. Yang, Michael S. Fuhrer and Mark T. Edmonds ()
Additional contact information
James L. Collins: Monash University
Anton Tadich: Monash University
Weikang Wu: Singapore University of Technology and Design
Lidia C. Gomes: National University of Singapore
Joao N. B. Rodrigues: National University of Singapore
Chang Liu: Monash University
Jack Hellerstedt: Monash University
Hyejin Ryu: Advanced Light Source, Lawrence Berkeley National Laboratory
Shujie Tang: Advanced Light Source, Lawrence Berkeley National Laboratory
Sung-Kwan Mo: Advanced Light Source, Lawrence Berkeley National Laboratory
Shaffique Adam: National University of Singapore
Shengyuan A. Yang: Singapore University of Technology and Design
Michael S. Fuhrer: Monash University
Mark T. Edmonds: Monash University

Nature, 2018, vol. 564, issue 7736, 390-394

Abstract: Abstract The electric-field-induced quantum phase transition from topological to conventional insulator has been proposed as the basis of a topological field effect transistor1–4. In this scheme, ‘on’ is the ballistic flow of charge and spin along dissipationless edges of a two-dimensional quantum spin Hall insulator5–9, and ‘off’ is produced by applying an electric field that converts the exotic insulator to a conventional insulator with no conductive channels. Such a topological transistor is promising for low-energy logic circuits4, which would necessitate electric-field-switched materials with conventional and topological bandgaps much greater than the thermal energy at room temperature, substantially greater than proposed so far6–8. Topological Dirac semimetals are promising systems in which to look for topological field-effect switching, as they lie at the boundary between conventional and topological phases3,10–16. Here we use scanning tunnelling microscopy and spectroscopy and angle-resolved photoelectron spectroscopy to show that mono- and bilayer films of the topological Dirac semimetal3,17 Na3Bi are two-dimensional topological insulators with bulk bandgaps greater than 300 millielectronvolts owing to quantum confinement in the absence of electric field. On application of electric field by doping with potassium or by close approach of the scanning tunnelling microscope tip, the Stark effect completely closes the bandgap and re-opens it as a conventional gap of 90 millielectronvolts. The large bandgaps in both the conventional and quantum spin Hall phases, much greater than the thermal energy at room temperature (25 millielectronvolts), suggest that ultrathin Na3Bi is suitable for room-temperature topological transistor operation.

Keywords: Binaural; Topological Phase Transition; Angle-resolved Photoelectron Spectroscopy (ARPES); Bulk Bandgap; Topological Insulators (search for similar items in EconPapers)
Date: 2018
References: Add references at CitEc
Citations:

Downloads: (external link)
https://www.nature.com/articles/s41586-018-0788-5 Abstract (text/html)
Access to the full text of the articles in this series is restricted.

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:nat:nature:v:564:y:2018:i:7736:d:10.1038_s41586-018-0788-5

Ordering information: This journal article can be ordered from
https://www.nature.com/

DOI: 10.1038/s41586-018-0788-5

Access Statistics for this article

Nature is currently edited by Magdalena Skipper

More articles in Nature from Nature
Bibliographic data for series maintained by Sonal Shukla () and Springer Nature Abstracting and Indexing ().