Bilayer Graphene Electronic Properties and Applications

Bilayer graphene, composed of two atomically thin sheets of carbon in Bernal (AB) stacking, exhibits electronic properties distinct from its monolayer counterpart. Interlayer coupling transforms the linear Dirac dispersion into tunable parabolic bands, while an applied perpendicular electric displacement field breaks inversion symmetry and opens an adjustable band gap. Substrate alignment can induce moiré superlattices, further modulating band structure and generating secondary Dirac points. The coexistence of spin, valley and layer pseudospin degrees of freedom endows bilayer graphene with a rich tapestry of quantum phenomena, including gate-controlled valley polarisation, specular electron focusing and topological transitions. These attributes have given rise to applications ranging from high-speed field-effect transistors and valleytronic interconnects to electrostatically defined quantum dots for spin- and valley-qubit realisation. The combination of exceptional carrier mobility, ambipolar transport and electrostatic tunability positions bilayer graphene as a versatile platform for next-generation nanoelectronic and quantum technologies.

Research from Nature Portfolio

Recent studies have employed high-resolution magneto-spectroscopy to resolve the fine low-energy band structure of Bernal bilayer graphene. By using Landau level spectroscopy as an energy marker, researchers have directly observed four distinct mini-Dirac cones and mapped displacement-field-induced topological transitions, thereby refining our understanding of electronic dispersion near neutrality. In parallel, work on electrostatically defined quantum dots has demonstrated a clear lifting of the fourfold spin and valley degeneracy, revealing a Kane–Mele-type spin–orbit coupling of tens of microelectronvolts and constraining disorder-induced valley mixing. Foundational advances in suspended bilayer devices have also shown that local dual-gate fields can open clean band gaps and create reproducible single-electron transport, paving the way for high-quality quantum confinement without edge or substrate disorder.

Bilayer Graphene Electronic Properties and Applications publication trend

The graph below shows the total number of articles in bilayer graphene electronic properties and applications across all publications each year (not limited to Nature Index journals).

Technical terms

Bernal stacking: The AB arrangement of two graphene layers enabling interlayer hopping and parabolic band dispersion.

Dirac cone: The linear energy–momentum relation around a K point in monolayer graphene; in bilayers, multiple mini-cones can emerge under low fields.

Displacement field: An external perpendicular electric field applied via dual gates to break layer symmetry and open a band gap.

Moiré potential: A spatially varying potential arising from slight lattice misalignment between graphene and its substrate, creating superlattice effects.

Landau level: Discrete electronic energy levels formed in a magnetic field, used as a spectroscopic tool to probe band structure.

Valley degree of freedom: The binary index (K or K′) of electronic states in graphene’s Brillouin zone, exploitable for information encoding.

Spin–orbit coupling: An interaction between an electron’s spin and its orbital motion, lifting degeneracies and enabling spin-based control.

Quantum dot: A nanoscale region of confined electrons in which discrete energy levels arise due to quantum confinement.

Trigonal warping: A distortion of the ideal parabolic bands in bilayer graphene into threefold symmetric pockets at low energies.

References

1. Probing the tunable multi-cone band structure in Bernal bilayer graphene. Nature Communications (2024).
2. Unveiling a Tunable Moiré Bandgap in Bilayer Graphene/hBN Device by Angle‐Resolved Photoemission Spectroscopy. Advanced Science (2025).
3. Specular Electron Focusing between Gate-Defined Quantum Point Contacts in Bilayer Graphene. Nano Letters (2023).
4. Spin and Valley States in Gate-Defined Bilayer Graphene Quantum Dots. Physical Review X (2018).
5. Gate-defined quantum confinement in suspended bilayer graphene. Nature Communications (2012).
6. Out-of-Plane Dielectric Susceptibility of Graphene in Twistronic and Bernal Bilayers. Nano Letters (2021).
7. Coherent Jetting from a Gate-Defined Channel in Bilayer Graphene. Physical Review Letters (2021).