P_ind: — | M_ind: — | σ_H surface: —
Axion electrodynamics: L_θ=(θα/4π²)E·B. TI: θ=π (quantized by T-symmetry). P=αθ/(4π²)B, M=αθ/(4π²)E. Surface: σ_H=(n+1/2)e²/h.