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arXiv · 2110.12303

Acoustic-phonon-mediated superconductivity in Bernal bilayer graphene

Yang-Zhi Chou·Fengcheng Wu·Jay D. Sau·Sankar Das Sarma
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Abstract

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 $T_c\sim 20$ mK near $n_e=-0.6\times 10^{12}$ 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.

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Yang-Zhi Chou, Fengcheng Wu, Jay D. Sau, Sankar Das Sarma. 2021-10-23. Acoustic-phonon-mediated superconductivity in Bernal bilayer graphene. https://doi.org/10.1103/physrevb.105.l100503

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