Oxide heterostructure with 10⁵ % electroresistance at room temperature

Many strongly correlated electron systems host a metal-insulator transition (MIT). The possibility to trigger it with moderate external stimuli has drawn a lot of attention on these materials. Several ways have been put forward to trigger the MIT (electrical pulses, 2D confinement, heating, ionic electromigration) but the application of the phenomenon in devices is limited by the fact the transition temperature is often imposed by the system.

We present a heterostructure of strongly correlated oxides whose resistance ranges from 2 kΩ under a 2 V direct polarisation to 2 MΩ under a 2 V inverse polarisation at room temperature. The mechanism of the transition is ascribed to the modification of the global conductivity as the chemical composition on both sides of the interface of the heterostructure is changed upon ionic migration induced by the external electric field. The conductivities of the metallic and insulating states depend on the temperature in such a way that the electroresistance is increased by a factor 10 at 10 K. The resistance switch is reversible at any temperature.

We will discuss the growth conditions of the heterostructure and detail the electrical states in direct and inverse polarisations. The possible integration in devices will be considered too.