Abstract
We report on the fabrication of a two-dimensional topological insulator Bi(111) bilayer on Sb nanofilms via a sequential molecular beam epitaxy growth technique. Our angle-resolved photoemission measurements demonstrate the evolution of the electronic band structure of the heterostructure as a function of the film thickness and reveal the existence of a two-dimensional spinful massless electron gas within the top Bi bilayer. Interestingly, our first-principles calculation extrapolating the observed band structure shows that, by tuning down the thickness of the supporting Sb films into the quantum dimension regime, a pair of isolated topological edge states emerges in a partial energy gap at 0.32 eV above the Fermi level as a consequence of quantum confinement effect. Our results and methodology of fabricating nanoscale heterostructures establish the Bi bilayer/Sb heterostructure as a platform of great potential for both ultra-low-energy-cost electronics and surface-based spintronics.
Original language | English (US) |
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Pages (from-to) | 3859-3864 |
Number of pages | 6 |
Journal | ACS Nano |
Volume | 10 |
Issue number | 3 |
DOIs | |
State | Published - Mar 22 2016 |
All Science Journal Classification (ASJC) codes
- General Engineering
- General Materials Science
- General Physics and Astronomy
Keywords
- Bi(111) bilayer
- Kane-Mele model
- quantum spin Hall effect
- quantum well states