Research on Superconductivity in Multilayer ABC-Stacked Graphene

Under the deformation potential model, the superconducting phenomenon in ABC-stacked multilayer graphene under a vertical electric field is investigated using linear combination operators and unitary transformation methods. Through the deformation potential model applied to a linear continuous medium, the effect of the external electric field is converted into the deformation potential energy of the crystal. Deformation potential phonons (LA phonons) act as propagators, generating electron-electron interactions. As the electric field increases, the ratio of the electric displacement vector to the dielectric function (D/ε) rises, leading to an increase in the electron ground-state energy, the opening of the band gap, and an enhancement of the attractive electron-electron interaction. With further increases in the external electric field, the deformation potential constant of the crystal (Dl) increases. When the phonon vibration frequency (ω) is around 8.5 THz, and the conditions are satisfied-where the wave vectors of different LA phonons are equal in magnitude and opposite in direction, and the electron spins are opposite-the attractive electron-electron interaction reaches its maximum (Heff), resulting in the emergence of superconductivity. Our study also provides a new perspective for understanding the unique quantum properties-such as strong correlations, superconductivity, and ferromagnetism-in different stacking configurations like AB, ABC, and ABCA.