Physical Origin of Transient Negative Capacitance in a Ferroelectric Capacitor

The unusual transient negative differential capacitance (NC) of a resistor--ferroelectric (FE) capacitor circuit is of keen interest for use in next-generation transistors, but a clear physical picture and theoretical framework are needed to interpret experiments. The authors show both numerically and analytically that transient NC comes from the mismatch of free charge and polarization in the capacitor during polarization switching, and a procedure to experimentally determine the viscosity coefficient in Landau theory is provided. These results should have real impact on metrology and device physics involving the NC effect.