Acoustic-Phonon-Mediated Superconductivity in Rhombohedral Trilayer Graphene

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Materials

Background:

• Two distinct superconducting phases were observed in moiréless ABC-stacked rhombohedral trilayer graphene.
• Understanding the pairing mechanism is crucial for explaining these phenomena.

Purpose of the Study:

• Investigate electron-acoustic-phonon coupling as a potential superconductivity pairing mechanism in trilayer graphene.
• Explain the origin of the two distinct superconducting phases observed experimentally.

Main Methods:

• Theoretical modeling of electron-acoustic-phonon interactions.
• Analysis of superconducting pairing states (s-wave spin-singlet, f-wave spin-triplet).
• Prediction of critical temperatures (T_{c}) as a function of doping and proximity to Van Hove singularities.

Main Results:

• Predicted superconductivity with critical temperatures (T_{c}) up to ~3 K near the Van Hove singularity.
• Finite T_{c} observed over a broad doping range away from the Van Hove singularity.
• Identified s-wave spin-singlet and f-wave spin-triplet pairings as dominant, yielding similar T_{c}.

Conclusions:

• Electron-acoustic-phonon coupling provides a viable mechanism for superconductivity in trilayer graphene.
• The theory explains the existence of two distinct superconducting phases.
• Suggests that superconductivity and other interaction-driven phases can arise from different fundamental mechanisms.