Strain-tunable topological quantum phase transition in buckled honeycomb lattices
- Department of Physics, Astronomy, and Geosciences, Towson University, 8000 York Road, Towson, Maryland 21252 (United States)
- Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701 (United States)
- Department of Physics, Washington University, St Louis, Missouri 63005 (United States)
Low-buckled silicene is a prototypical quantum spin Hall insulator with the topological quantum phase transition controlled by an out-of-plane electric field. We show that this field-induced electronic transition can be further tuned by an in-plane biaxial strain ε, owing to the curvature-dependent spin-orbit coupling (SOC): There is a Z{sub 2} = 1 topological insulator phase for biaxial strain |ε| smaller than 0.07, and the band gap can be tuned from 0.7 meV for ε=+0.07 up to 3.0 meV for ε=−0.07. First-principles calculations also show that the critical field strength E{sub c} can be tuned by more than 113%, with the absolute values nearly 10 times stronger than the theoretical predictions based on a tight-binding model. The buckling structure of the honeycomb lattice thus enhances the tunability of both the quantum phase transition and the SOC-induced band gap, which are crucial for the design of topological field-effect transistors based on two-dimensional materials.
- OSTI ID:
- 22399016
- Journal Information:
- Applied Physics Letters, Vol. 106, Issue 18; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
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