Nonlinear response of microwave impedance microscopy

Microwave impedance microscopy (MIM) is an emerging scanning probe technique that allows non-contact measurement of local linear complex permittivity with nanometer spatial resolution. In this work, we extend traditional MIM to nonlinear operation to probe local electrical nonlinearity. We develop a quantitative framework relating the multi-harmonic MIM signals to nonlinear tip–sample admittance using a nonlinear circuit responsivity model and validate our results with high-precision time-domain numerical simulations. We provide practical guidance on implementing and calibrating such nonlinear MIM and discuss implications for new material and device applications enabled by its nonlinear capabilities.