  The Boltzmann distribution of electrons poses a fundamental barrier to
lowering energy dissipation in conventional electronics, often termed as
Boltzmann Tyranny. Negative capacitance in ferroelectric materials, which stems
from the stored energy of phase transition, could provide a solution, but a
direct measurement of negative capacitance has so far been elusive. Here we
report the observation of negative capacitance in a thin, epitaxial
ferroelectric film. When a voltage pulse is applied, the voltage across the
ferroelectric capacitor is found to be decreasing with time-in exactly the
opposite direction to which voltage for a regular capacitor should change.
Analysis of this inductance-like behavior from a capacitor presents an
unprecedented insight into the intrinsic energy profile of the ferroelectric
material and could pave the way for completely new applications.
