Negative capacitance in a field effect transistor is not new. In fact this has been shown mire than a decade ago. The reason it won't make its way into modern chips is because the materials used to make the ferroelectrics aren't CMOS foundry compatible.

Hafnium and zirconium dioxide are CMOS foundry compatible.

Hafnium dioxide has been the gate dielectric for MOS transistors in all dense CMOS processes for a couple of decades. It is certainly used in whatever smartphone or computer you have.

With the former gate dielectric, silicon dioxide, it was impossible to make MOS transistors as small as in modern processes, because it has a too low dielectric constant, which would have required impossibly thin gate layers (for high enough gate capacitances).

Hafnium dioxide has a much higher dielectric constant, allowing to achieve the same gate capacitance at a manageable gate thickness.

The chemical behaviors of hafnium and zirconium are almost identical, their similarity being as great as between rare-earth elements, but for the dielectric behavior of their oxide the substitution of a fraction of the hafnium with zirconium and appropriate treatments can make the oxide ferroelectric.

Many great applications have been proposed for ferroelectric Hf-Zr dioxide already for some years, but I have not heard of any commercial device. The reason is not any compatibility problem with CMOS processes, but I believe that it might be hard to obtain reproducible ferroelectric properties, as they might vary a lot depending on the exact parameters of the manufacturing steps.