Reentrant magic-angle phenomena in twisted bilayer graphene in integer magnetic fluxes

In this Letter we address the reentrance of magic-angle phenomena (band flatness and quantum-geometric transport) in twisted bilayer graphene (TBG) subjected to strong magnetic fluxes $\ifmmode\pm\else\textpm\fi{}{\mathrm{\ensuremath{\Phi}}}_{0},\ifmmode\pm\else\textpm\fi{}2{\mathrm{\ensuremath{\Phi}}}_{0},\ifmmode\pm\else\textpm\fi{}3{\mathrm{\ensuremath{\Phi}}}_{0}...$ (${\mathrm{\ensuremath{\Phi}}}_{0}=h/e$ is flux quantum per moir\'e cell). The translation invariance restored at integer fluxes, for which calculate TBG band structure using accurate atomistic models with lattice relaxations. Similarly zero-flux physics outside condition, reported effect breaks down rapidly twist. We conclude that reemerges high fields, witnessed by appearance flat electronic bands distinct from Landau levels, manifesting nontrivial geometry. further discuss possible flat-band geometric contribution superfluid weight fields (28 T $1.{08}^{\ensuremath{\circ}}$ twist), according Peotta-T\"orm\"a mechanism [Nat. Commun. 6, 8944 (2015)].