A common method of controlling the chemical potential in topological insulators is applying a gate electrode. Simultaneously applying high source-drain bias currents in such devices can lead to parasitic effects due to the presence of a gate electrode, not intrinsic to the topological insulator. We derive that these parasitic effects lead to a gradient in the Hall effect along the current lead of a Hall bar. Consequently, nonreciprocal effects in both longitudinal and Hall voltages appear upon reversing the bias. These effects scale similarly to the magnetochiral anisotropy, requiring detailed analysis to make a distinction. Experimentally we show that nonreciprocal effects can appear in materials where magnetochiral anisotropy is not expected while a top gate is present. Without the gate electrode, this nonreciprocal effect is found to be absent. These results show the significance of considering and, if possible, excluding gate electrode-induced effects when searching for nonreciprocal resistance intrinsic to a material.

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• Dielectric properties
• Hall effect
• Magnetoresistance
• Metrology
• Non-reciprocal propagation
• Dilute magnetic topological insulators
• Hall bar
• Resistivity measurements