Figure4

Figure 4. Experimental studies of the nonlinear Hall response in topological antiferromagnetic heterostructure (BP/MnBi₂Te₄) and twisted bilayer graphene. (A) Optical second harmonic generation measurements of a 6 SLs MnBi₂Te₄ before and after being coupled with BP. (B) The $$ V_{yxx}^{2\omega} $$ and $$ V_{xx}^{\omega} $$ before and after being coupled with BP. (C) The $$ E_{Z} $$ dependence of the $$ \sigma_{yxx}^{2\omega} $$ and $$ R_{xx} $$. (D) Phase diagram of the nonlinear Hall effect. The dominated mechanism changes with strain strength and effective disorder density, with red (blue) regions indicating dipole (scattering) dominance. (E) The $$ V_{\bot}^{2\omega} $$ varies with $$ \upsilon $$ and D. (A-C) reprinted with permission^[27], Copyright 2023, The American Association for the Advancement of Science. (D and E) reprinted with permission^[93], Copyright 2023, The American Physical Society.