Systematic Kohn–Luttinger analysis for accurate Tc in rhombohedral tetralayer graphene

Develop a systematic Kohn–Luttinger analysis to obtain a more accurate quantitative estimate of the superconducting transition temperature Tc for intravalley spin-polarized superconductivity in rhombohedral tetralayer graphene by averaging over different scattering momenta (kC values) and relaxing the constraint |k|=|k'| in the screened Coulomb interaction.

Background

The paper argues that a Kohn–Luttinger mechanism arising from screened Coulomb interactions is a plausible origin of intravalley spin-polarized superconductivity in rhombohedral tetralayer graphene. Using a static RPA approach, the authors estimate effective angular-momentum channel couplings from a sparse k-grid and a simplified projection onto a circle of radius kC to obtain g1 and Tc.

They explicitly note that a more accurate determination of Tc requires averaging over different kC and relaxing the |k|=|k'| constraint; they defer this systematic investigation to future studies to improve quantitative precision beyond their current simplified treatment.

References

To estimate the g_1 more accurately, we also need to average over different k_C and relax the condition |k|=|k'|. A systematic investigation of the Kohn-Luttinger mechanism should provide a better quantitative estimate of the T_c, which we defer for future studies.

— Intravalley spin-polarized superconductivity in rhombohedral tetralayer graphene  (2409.06701 - Chou et al., 2024) in Section 6 (Possible pairing origin: Kohn-Luttinger mechanism)