Repulsive-Interaction-Driven Topological Superconductivity in a Landau Level Coupled to an s-Wave Superconductor

Area of Science:

• Condensed Matter Physics
• Quantum Materials
• Topological States of Matter

Background:

• Topological superconductors are exotic states with potential for fault-tolerant quantum computing.
• Proximity coupling of topological insulators to s-wave superconductors is a known route to topological superconductivity.
• Noninteracting electrons in a Landau level with Rashba spin-orbit coupling typically fail to form topological superconductors when coupled to s-wave superconductors.

Purpose of the Study:

• To investigate the role of electron-electron interactions in the formation of topological superconductivity in a half-filled Landau level.
• To explore an alternative mechanism for achieving topological superconductivity beyond noninteracting electron models.

Main Methods:

• Exact diagonalization techniques were employed to study the electron system.
• The model considered a partially filled Landau level with Rashba spin-orbit coupling and repulsive interactions.
• Proximity coupling to an ordinary s-wave superconductor was simulated.

Main Results:

• Repulsive interactions were shown to induce topological superconductivity in a half-filled Landau level.
• This phenomenon was observed for a range of interaction parameters.
• The presence of a conventional Abrikosov vortex lattice did not prevent the emergence of topological superconductivity.

Conclusions:

• Repulsive interactions can be a key ingredient for realizing topological superconductivity in certain quantum Hall systems.
• Coupling a composite Fermi liquid (formed by repulsive interactions) to an s-wave superconductor presents a viable strategy for creating topological superconductors.