Giant Nonlinear Tunneling Current in HfO₂-based Anti-Ferroelectric Tunnel Junction

Owing to the recent advances in the oxide growth technology, ferroelectricity has been stabilized even in a few nm-thick films, which makes it possible to realize the ultrathin oxides-based ferroelectric tunneling junctions (FTJs) useful for the next generation switchable diode. Among various ferroelectric oxides, HfO₂ is the most promising material for FTJ devices since it has the great advantage of complementary metal-oxide-semiconductor (CMOS) process compatibility. Despite their numerous advantages, low non-linearity and tunneling current have hindered their applications to electronic devices. Here, combining density functional theory (DFT) calculations and numerical tunneling current simulations of the new type of tunneling potential, we find that the antiferroelectric-like head-to-head and tail-to-tail polarizations significantly enhance the non-linearity (>10³) and tunneling current at the same time, which will be an essential guideline to design high density and low power consumption electronics applications.