Phase transition and topological transistors based on monolayer Na3Bi nanoribbons.
Nanoscale
; 13(35): 15048-15057, 2021 Sep 17.
Article
in En
| MEDLINE
| ID: mdl-34533149
ABSTRACT
Recently, a topological-to-trivial insulator quantum-phase transition induced by an electric field has been experimentally reported in monolayer (ML) and bilayer (BL) Na3Bi. A narrow ML/BL Na3Bi nanoribbon is necessary to fabricate a high-performance topological transistor. By using the density functional theory method, we found that wider ML Na3Bi nanoribbons (>7 nm) are topological insulators, featured by insulating bulk states and dissipationless metallic edge states. However, a bandgap is opened for extremely narrow ML Na3Bi nanoribbons (<4 nm) due to the quantum confinement effect, and its size increases with the decrease in width. In the topological insulating ML Na3Bi nanoribbons, a bandgap is opened in the metallic edge states under an external displacement electric field, with strength (â¼1.0 V Å-1) much smaller than the reopened displacement electric field in ML Na3Bi (3 V Å-1). An ultrashort ML Na3Bi zigzag nanoribbon topological transistor switched by the electrical field was calculated using first-principles quantum transport simulation. It shows an on/off current/conductance ratio of 4-71 and a large on-state current of 1090 µA µm-1. Therefore, a proof of the concept of topological transistors is presented.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Nanoscale
Year:
2021
Document type:
Article