▎ 摘　　要

Trilayer graphene with a twisted middle layer has recently emerged as a new platform exhibiting correlated phases and superconductivity near its magic angle. A detailed characterization of its electronic structure in the parameter space of twist angle theta, interlayer potential difference Delta, and top-bottom layer stacking tau reveals that flat bands with large Coulomb energy versus bandwidth U/W > 1 are expected within a range of +/- 0.2 degrees near theta similar or equal to 1.5 degrees and theta similar or equal to 1.2 degrees for tau(AA) top-bottom layer stacking, between a wider 1 degrees -1.7 degrees range for tau(AB) stacking, whose bands often have finite valley Chern numbers thanks to the opening of primary and secondary band gaps in the presence of a finite Delta, and below theta less than or similar to < 0.6 degrees for all tau considered. The largest U/W ratios are expected at the magic angle similar to 1.5 degrees when vertical bar Delta vertical bar similar to 0 meV for AA, and slightly below near similar to 1.4 degrees for finite vertical bar Delta vertical bar similar to 25 meV for AB stackings, and near theta similar to 0.4 degrees for both stackings. When tau is the saddle point stacking vector between AB and BA we observe pronounced anisotropic local density of states (LDOS) strip patterns with broken triangular rotational symmetry. We present optical conductivity calculations that reflect the changes in the electronic structure introduced by the stacking and gate tunable system parameters.