Fig. 3: The Hall angle and scaling relation as a function external current.

The magnetic field dependence of the Hall angle σ_xy/σ_xx at I = 2 mA (a) and I = 3 mA (b) for selected temperatures; the gray band marks a crossover region between Ψ_C and Ψ_T. Note that the gray area is approximately defined, and mainly serves as a guide to the eye. c–i The scaling relation σ_xy ∝ σ_xx^α at T = 30 K for selected currents I. The shaded areas indicate a regime of Ψ_T having a lower value of the exponent α; the arrows indicate the cutoff field. j The scaling relation σ_xy ∝ σ_xx^1.8 at T = 100 K and I = 1 mA. k σ_xx (left scale) and σ_xy (right scale) as a function of H || c axis at T = 30 K and I = 2 mA; the marked field 8.3 T indicates a crossover field above which σ_xy rises much faster than σ_xx. l The phase diagram of the exponent α as a function of external current I. Note that Ψ_C features 3 ≤ α = α_HF < 5 (yellow shaded area) whereas Ψ_T 1 ≤ α = α_LF < 2.2 (gray shaded area). Note that α_c corresponds that for Ψ_C, and α_T for Ψ_T.