Fig. 4: Landau level spreading of a flat-band system with space–time-inversion symmetry.
From: Geometric characterization of anomalous Landau levels of isolated flat bands
a The lattice structure for the IST-symmetric checkerboard model. The red and black lines denote the hopping processes between A and B sublattices. b The band structure of \({H}_{{I}_{{{{{{{{\rm{ST}}}}}}}}}}({{{{{{{\bf{k}}}}}}}})\) with t = 1.0. c The Hofstadter spectrum of the IST-symmetric checkerboard model with t = 1.0. d Variation of the lowest and highest Landau levels related to the flat band in the weak magnetic field (blue and black circles). \({E}_{{{{{{{{\rm{fb}}}}}}}},\min }(\phi /{\phi }_{0})\) and \({E}_{{{{{{{{\rm{fb}}}}}}}},\max }(\phi /{\phi }_{0})\) indicate the corresponding fitting functions (red and black solid lines) that exhibit quadratic magnetic field dependence dominantly.
