Nonpolar resistance switching of metal/binary-transition-metal oxides/metal sandwiches: homogeneous/inhomogeneous transition of current distribution

TL;DR

This paper investigates the nonpolar resistance switching in metal/binary-transition-metal oxides/metal sandwiches, revealing that the switching involves a transition between homogeneous and inhomogeneous current distributions at the interface, which is crucial for nonvolatile memory applications.

Contribution

It uncovers the physical mechanism behind resistance switching in binary TMO sandwiches, emphasizing the homogeneous/inhomogeneous current transition at interfaces as a key factor.

Findings

Resistance switches reversibly between high and low states.

Switching involves homogeneous and inhomogeneous current distribution transitions.

Universal features include nonpolar and threshold switching, and current-voltage duality.

Abstract

Exotic features of a metal/oxide/metal (MOM) sandwich, which will be the basis for a drastically innovative nonvolatile memory device, is brought to light from a physical point of view. Here the insulator is one of the ubiquitous and classic binary-transition-metal oxides (TMO), such as Fe2O3, NiO, and CoO. The sandwich exhibits a resistance that reversibly switches between two states: one is a highly resistive off-state and the other is a conductive on-state. Several distinct features were universally observed in these binary TMO sandwiches: namely, nonpolar switching, non-volatile threshold switching, and current--voltage duality. From the systematic sample-size dependence of the resistance in on- and off-states, we conclude that the resistance switching is due to the homogeneous/inhomogeneous transition of the current distribution at the interface.