▎ 摘　　要

We investigate the electronic structure of alternating-twist triple Bernal-stacked bilayer graphene (t3BG) as a function of interlayer coupling omega, twist angle theta, interlayer potential difference Delta, and top-bottom bilayers sliding vector tau for three possible configurations AB/AB/AB, AB/BA/AB, and AB/AB/BA. The parabolic low-energy band dispersions in a Bernal-stacked bilayer and gap opening through a finite interlayer potential difference Delta allows the flattening of bands in t3BG down to similar to 20 meV for twist angles theta less than or similar to 2 degrees regardless of the stacking types. The easier isolation of the flat bands and associated reduction of Coulomb screening thanks to the intrinsic gaps of bilayer graphene for finite Delta facilitate the formation of correlation-driven gaps when it is compared to the metallic phases of twisted trilayer graphene under electric fields. We obtain the stacking dependent Coulomb energy versus bandwidth U/W greater than or similar to 1 ratios in the theta and Delta parameter space. We also present the expected K-valley Chern numbers for the lowest-energy nearly flat bands.