Hofstadter 1976: 2D electron in periodic potential + magnetic field shows fractal energy spectrum vs flux-per-plaquette phi/phi_0 (rational vs irrational); experimentally observed in graphene/hBN moire (Dean 2013, Hunt 2013).
Hofstadter 1976: 2D electron in periodic potential + magnetic field shows fractal energy spectrum vs flux-per-plaquette phi/phi_0 (rational vs irrational); experimentally observed in graphene/hBN moire (Dean 2013, Hunt 2013).