Acoustic-phonon-mediated superconductivity in moiréless graphene multilayers

Yang-Zhi Chou, Fengcheng Wu, Jay D. Sau, and Sankar Das Sarma
Phys. Rev. B 106, 024507 – Published 8 July 2022

Abstract

We investigate the competition between acoustic phonon mediated superconductivity and the long-range Coulomb interaction in moiréless graphene multilayers, specifically, Bernal bilayer graphene, rhombohedral trilayer graphene, and ABCA-stacked tetralayer graphene. In these graphene multilayers, the acoustic phonons can realize, through electron-phonon coupling, both spin-singlet and spin-triplet pairings, and the intra-sublattice pairings (s-wave spin-singlet and f-wave spin-triplet) are the dominant channels. Our theory naturally explains the distinct recent experimental findings in Bernal bilayer graphene and rhombohedral trilayer graphene, and we further predict the existence of superconductivity in ABCA tetralayer graphene arising from electron-phonon interactions. In particular, we demonstrate that the acoustic phonon mediated superconductivity prevails over a wide range of doping in rhombohedral trilayer graphene and ABCA tetralayer graphene while superconductivity exists only in a narrow range of doping near the Van Hove singularity in Bernal bilayer graphene. Key features of our theory are the inclusion of realistic band structures with the appropriate Van Hove singularities and Coulomb repulsion effects (the so-called “μ* effect”) opposing the phonon-induced superconducting pairing. We also discuss how intervalley scatterings can suppress the spin-triplet spin-polarized superconductivity. Our work provides detailed prediction based on electron–acoustic phonon interaction induced graphene superconductivity, which should be investigated in future experiments.

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  • Received 3 May 2022
  • Revised 24 June 2022
  • Accepted 27 June 2022

DOI:https://doi.org/10.1103/PhysRevB.106.024507

©2022 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Yang-Zhi Chou1,*, Fengcheng Wu2,3, Jay D. Sau1, and Sankar Das Sarma1

  • 1Condensed Matter Theory Center and Joint Quantum Institute, Department of Physics, University of Maryland, College Park, Maryland 20742, USA
  • 2School of Physics and Technology, Wuhan University, Wuhan 430072, China
  • 3Wuhan Institute of Quantum Technology, Wuhan 430206, China

  • *yzchou@umd.edu

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Issue

Vol. 106, Iss. 2 — 1 July 2022

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