We present a systematic theory of acoustic-phonon-mediated superconductivity, which incorporates Coulomb repulsion, explaining the recent experiment in Bernal bilayer graphene under a large displacement field. The acoustic-phonon mechanism predicts that s-wave spin-singlet and f-wave spin-triplet pairings are degenerate and dominant. Assuming a spin-polarized valley-unpolarized normal state, we obtain f-wave spin-triplet superconductivity with a Tc∼20 mK near ne=−0.6×1012 cm−2 for hole doping, in approximate agreement with the experiment. We further predict the existence of superconductivity for larger doping in both electron-doped and hole-doped regimes. Our results indicate that the observed spin-triplet superconductivity in Bernal bilayer graphene arises from acoustic phonons.
@article{arxiv.2110.12303,
title = {Acoustic-phonon-mediated superconductivity in Bernal bilayer graphene},
author = {Yang-Zhi Chou and Fengcheng Wu and Jay D. Sau and Sankar Das Sarma},
journal= {arXiv preprint arXiv:2110.12303},
year = {2022}
}