Andreev and normal reflections in gapped bilayer graphene-superconductor junctions
arXiv:2306.00529 · doi:10.1103/PhysRevB.108.184510
Abstract
We study the Andreev and normal reflection processes -- retro as well as specular -- in a bilayer graphene-superconductor junction where equal and opposite displacement fields are applied for the top and bottom layers to induce a band gap. By employing the Dirac-Bogoliubov-de Gennes equation for the gapped bilayer graphene-superconductor junction, we calculate the reflections probabilities within the scattering theory approach. The subgap conductance, calculated in the framework of Blonder-Tinkham-Klapwijk formalism, shows the contribution from the Andreev retro-reflection (specular-reflection) when the applied bias voltage is below (above) the Fermi energy. Notably, both retro and specular reflections are modified in the presence of the displacement field, and the retro-to-specular crossover gets amplified when the displacement field is relatively small. They can be further tuned to either specular or retro Andreev reflection by adjusting the Fermi energy. Furthermore, our study reveals the simultaneous existence of double Andreev reflections and double normal reflections when the displacement field becomes comparable to the interlayer coupling strength. The existence of the normal retro-reflection process in a bilayer graphene-superconductor junction is a new finding which shows a distinctive feature in the conductance that can be experimentally verified.
arXiv comment12 pages, 11 figures
References in corpus (37)
- The electronic properties of graphene
- Two-Dimensional Gas of Massless Dirac Fermions in Graphene
- Experimental Observation of Quantum Hall Effect and Berry's Phase in Graphene
- Chiral tunneling and the Klein paradox in graphene
- Landau level degeneracy and quantum Hall effect in a graphite bilayer
- Unconventional quantum Hall effect and Berry's phase of 2pi in bilayer graphene
- Gate-induced insulating state in bilayer graphene devices
- Andreev reflection and Klein tunneling in graphene
- Asymmetry gap in the electronic band structure of bilayer graphene
- The electronic properties of bilayer graphene
- Specular Andreev reflection in graphene
- Quantum Monte Carlo Calculation of the Binding Energy of Bilayer Graphene
- Electronic Transport in Dual-gated Bilayer Graphene at Large Displacement Fields
- Tunneling conductance of graphene NIS junctions
- Specular Interband Andreev Reflections in Graphene
- Proximity and Josephson effects in superconductor - two dimensional electron gas planar junctions
- Tunneling conductance in - and d-wave superconductor-graphene junctions: Extended Blonder-Tinkham-Klapwijk formalism
- Fabry-Pérot interference in gapped bilayer graphene with broken anti-Klein tunneling
- Bilayer graphene with single and multiple electrostatic barriers: band structure and transmission
- Dirac-fermions and conductance-oscillations in (s,d)-wave superconductor/normal graphene junctions
- Tuning anti-Klein to Klein tunneling in bilayer graphene
- Zero-bias conductance peak and Josephson effect in graphene-NbTiN junctions
- Detecting entangled states in graphene via crossed Andreev reflection
- Andreev reflection near the Dirac point at Graphene - NbSe2 junction
- Valley subband splitting in bilayer graphene quantum point contact
- Andreev reflection in bilayer graphene
- A Ballistic Graphene Cooper Pair Splitter
- Cross-over from retro to specular Andreev reflections in bilayer graphene
- Enhanced Specular Andreev reflection in bilayer graphene
- Imaging Andreev Reflection in Graphene
- Tailoring supercurrent confinement in graphene bilayer weak links
- Enhanced Andreev reflection in gapped graphene
- Double Andreev reflections and double normal reflections in nodal-line semimetal-superconductor junctions
- Andreev reflection in ballistic normal metal/graphene/superconductor junctions
- Andreev Reflection and Klein Tunneling in High-Temperature Superconductor/Graphene Junctions
- Andreev Reflection in a Bilayer Graphene Junction: Role of Spatial Variation of the Charge Neutrality Point
- Energy distribution controlled ballistic Josephson junction