Gate-Defined Topological Josephson Junctions in Bernal Bilayer Graphene.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Computing

Background:

• Recent experiments show Bernal bilayer graphene (BLG) on monolayer WSe2 exhibits robust superconductivity.
• This system also displays sizable induced spin-orbit coupling.
• Superconductivity in this heterostructure emerges from a parent state with intervalley coherence.

Purpose of the Study:

• Propose Bernal bilayer graphene/WSe2 as a platform for engineered topological Josephson junctions.
• Investigate the potential for Majorana zero-energy modes in this system.
• Explore a pathway for internally engineered topological superconductivity.

Main Methods:

• Theoretical proposal for gate-defined planar topological Josephson junctions.
• Analysis of superconductivity in BLG/WSe2 with intervalley coherence.
• Inclusion of weak in-plane magnetic fields to induce Majorana modes.

Main Results:

• Superconductivity and induced spin-orbit coupling coexist in BLG/WSe2.
• Topological Josephson junctions can be engineered within this material system.
• Majorana zero-energy modes are predicted to form in the barrier region under specific conditions.

Conclusions:

• The BLG/WSe2 heterostructure is a promising platform for realizing topological superconductivity.
• This approach minimizes detrimental effects from disorder and orbital magnetic fields.
• The findings pave the way for novel quantum devices and topological quantum computing applications.