Erasable Ferroelectric Domain Wall Diodes* *Supported by the National Key Basic Research Program of China (Grant No. 2019YFA0308500), the Basic Research Project of Shanghai Science and Technology Innovation Action (Grant No. 17JC1400300), and the National Natural Science Foundation of China (Grant Nos. 61674044 and 61904034).

Abstract

The unipolar diode-like domain wall currents in LiNbO3 single-crystal nanodevices are not only attractive in terms of their applications in nonvolatile ferroelectric domain wall memory, but also useful in half-wave and full-wave rectifier systems, as well as detector, power protection, and steady voltage circuits. Unlike traditional diodes, where the rectification functionality arises from the contact between n-type and p-type conductors, which are unchanged after off-line production, ferroelectric domain wall diodes can be reversibly created, erased, positioned, and shaped, using electric fields. We demonstrate such functionality using ferroelectric mesa-like cells, formed at the surface of an insulating X-cut LiNbO3 single crystal. Under the application of an in-plane electric field above a coercive field along the polar Z axis, the domain within the cell is reversed to be antiparallel to the unswitched bottom domain via the formation of a conducting domain wall. The wall current was rectified using two interfacial volatile domains in contact with two side Pt electrodes. Unlike the nonvolatile inner domain wall, the interfacial domain walls disappear to turn off the wall current path after the removal of the applied electric field, or under a negative applied voltage, due to the built-in interfacial imprint fields. These novel devices have the potential to facilitate the random definition of diode-like elements in modern large-scale integrated circuits.