Nonlinear charge transport, such as nonreciprocal longitudinal resistance and nonlinear Hall effect, has attracted considerable interest in probing the symmetries and topological properties of new materials. Recent research has revealed significant nonreciprocal longitudinal resistance and nonlinear Hall effect in MnBi₂Te₄, an intrinsic magnetic topological insulator, induced by the quantum metric dipole. However, the inconsistent response with charge density and conflicting C_3z symmetry requirement necessitate a thorough understanding of factors affecting the nonlinear transport measurement. This study uncovers an experimental factor leading to significant nonlinear transport signals in MnBi₂Te₄, attributed to gate voltage oscillation from the application of large alternating current. Additionally, a methodology is proposed to suppress this effect by individually grounding the voltage electrodes during second-harmonic measurements. The investigation underscores the critical importance of assessing gate voltage oscillation’s impact before determining the intrinsic nature of nonlinear transport in 2D material devices with an electrically connected operative gate electrode.

非线性电荷传输，如非互易纵向电阻和非线性霍尔效应，在探索新材料的对称性和拓扑特性方面引起了相当大的兴趣。最近的研究揭示了由量子度量偶极子诱导的本征磁性拓扑绝缘体 MnBi₂Te₄ 中存在显著的非互易纵向电阻和非线性霍尔效应。然而，与电荷密度的不一致响应和相互冲突的 C_3z 对称性要求需要彻底了解影响非线性输运测量的因素。本研究揭示了导致 MnBi₂Te₄ 中产生显着非线性传输信号的实验因素，该因素归因于大交流电施加的栅极电压振荡。此外，还提出了一种通过在二次谐波测量期间将电压电极单独接地来抑制这种影响的方法。该研究强调了在确定具有电连接操作栅极电极的 2D 材料器件中非线性传输的内在本质之前评估栅极电压振荡影响的至关重要性。