Low-voltage operation of high-density ferroelectric domain wall memory

Nonvolatile ferroelectric domain wall memory was fabricated using X-cut single-crystal LiNbO3 thin films bonded to SiO2/Si wafers, where each LiNbO3 mesa cell was etched in contact to two side Pt metal electrodes. In-plane electric-field poling along the polar Z axis above a coercive field of 750 kV/cm induced non-volatile switching of ferroelectric domains in the cell with domain walls (DWs) created within the substrate. The DWs are erasable and electrically conductive in a high on-off ratio (>106), showing potential for application in a large-scale crossbar memory. However, the coercive field is too high to prevent low-voltage operations of the memory in a fast switching speed and low-energy consumption. Here we exhibited a method to lower the coercive field significantly by introduction of the reversed seeding domain under one electrode that extends over the cell surface slightly. The seeds facilitate the wall sideways motion in a small driving field, paving the way toward the low-voltage manipulation of domain wall nanodevices.