Electric field-induced tunable insulator-to-metal transition at room-temperature in NiO/ferroelectric heterostructures

This paper presents a wafer-scale NiO ( a prototype Mott material) /ferroelectric heterostructure termed as FeMott capable of room-temperature operation as a gate tunable electrical switch in deep contrast with existing Mott transistors which are working at around 70 0 C being based on VO 2 which is the most used Mott material. Here, FeMott devices are made using NiO which shows a reversible insulator-metal transition (IMT) first investigated by Mott, being the first known Mott material. We show that integrating NiO with an yttrium-doped HfO 2 (HfYO) ferroelectric layer enables electrical switching through an electrically induced IMT. This switching mechanism is attributed to electronic interactions between NiO and HfYO, which possesses a significant remanent polarization of 80 C/cm² and a coercive electric field of 2.7MV/cm at room temperature. The device exhibits gate voltage control of the IMT starting at 1 V, resulting in a high ON/OFF ratio of five orders of magnitude.