Local Spectroscopy of Magnetic Bloch States and Hofstadter Hyperorbits in Bernal Bilayer Graphene on hBN Moiré Superlattice

The Hofstadter butterfly represents a remarkable fractal energy spectrum emerging from the interplay between magnetic Bloch states and Landau quantization. Using ultra–low-temperature scanning tunneling microscopy and spectroscopy (ULT-STM/STS), we investigate Bernal bilayer graphene aligned with a bottom hBN, where a ~10 nm moiré potential induces a tunable Hofstadter regime. As the magnetic flux approaches rational fractions of the flux quantum, the Landau levels evolve into q-fold magnetic Bloch minibands, acquiring distinct spectral features. High-resolution local density-of-states (LDOS) spectra directly visualize this miniband formation and its reorganization with carrier density and magnetic field, offering a local perspective on moiré-modulated cyclotron motion. Gate-dependent measurements further reveal Chern-indexed gap trajectories and signatures of interaction-driven flavor symmetry breaking. Together, these results demonstrate high resolution STM/STS as a powerful tool for probing magnetic Bloch topology and correlated miniband formation in low dimensional material systems.