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Published on: June 28, 2018
Topological phase transition induced by spin-orbit coupling in bilayer graphene
Lei Xu1, Yuan Zhou, Chang-De Gong
1National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, People's Republic of China.
Summary
We explore topological phase transitions in biased bilayer graphene, revealing complex behaviors driven by spin-orbit couplings. Tuning bias voltage controls these transitions, impacting topological insulator and quantum valley Hall phases.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Mechanics
Background:
- Bilayer graphene systems are platforms for studying topological phenomena.
- Spin-orbit couplings (SOC) significantly influence electronic properties and topological phases.
- Understanding phase transitions is crucial for designing novel electronic devices.
Purpose of the Study:
- Investigate topological phase transitions in biased bilayer graphene.
- Analyze the roles of intrinsic and Rashba spin-orbit couplings.
- Determine the stability of topological phases under external fields.
Main Methods:
- Theoretical modeling of biased bilayer graphene.
- Analysis of bulk band gap evolution.
- Parameter-dependent phase diagrams construction.
- Investigation of stability against exchange fields and symmetry breaking.
Main Results:
- Complex topological phase transitions observed, dependent on system parameters.
- Transitions involve bulk band gap closing and reopening.
- Tunable transitions achieved via bias voltage.
- Topological insulator and quantum valley Hall phases exhibit distinct stability conditions.
Conclusions:
- Biased bilayer graphene hosts rich topological physics controlled by SOC and bias.
- Stability of topological phases is sensitive to the interplay of intrinsic/Rashba SOC and symmetry breaking.
- The findings offer insights into controlling topological states in 2D materials.
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