Negative capacitance in the hexagonal-YbFeO₃ epitaxial thin films

The management of the heat generation and the power dissipation during information processing are very import issues in highly integrated electronic circuits. The ferroelectric negative capacitance (NC) effects, which was proposed to overcome the fundamental limit posed by the Boltzmann distribution of electrons, are attracting a great deal of interests. This work, we designed a heterostructure based on the hexagonal-YbFeO₃ (h-YbFO) multiferroic thin films to study the transient NC effects. For the first time, room-temperature ferroelectric properties in the epitaxial h-YbFO thin films and a direct observation of NC effects of h-YbFO thin films are reported. The transient NC effects as a function of the load resistance and applied source voltage are systematically investigated, which qualitatively follow the theoretical prediction. The structural requirements for the NC effects have been discussed, e.g. domain structure correlation with dielectric layers, grain size effects, microscopy mechanisms of ferroelectric switching. This work provides a new platform for the study of NC effects, and opens new horizons for understanding and improving the NC effects.