Conductive mechanism in memristor at the thinnest limit: The case based on monolayer boron nitride

Atomic picture and electronic transport property are taken into account to investigate the nonvolatile resistive switching mechanism of a memristor at the thinnest limit, just based on one monolayer hexagonal boron nitride (h-BN). It is demonstrated that the intrinsic van der Waals gaps between electrodes and monolayer h-BN ensure the high resistance state (HRS). However, the absorption/desorption of a metallic-electrode atom on the one side of the h-BN can hardly switch the device to hold the experimentally observed ON/OFF current ratio. It is proposed that the electrode atom should penetrate the h-BN sheet via boron vacancy (VB) to form a full conductive atomic filament for an effective low resistance state. The current signal of this VB pinning Au conductive filament can reach up to three orders of magnitude higher than that of the HRS. The energy barrier for one Au atom to pass through VB is also reasonably as low as 0.832 eV. Molecular dynamics simulation further manifests the nonvolatility of this atomic conductive filament at the limit that could even maintain stability at 500 K. This work offers a key working picture in memristors at their thinnest limit, which provides a valuable reference to the development of emerging memory/computing devices at the ultrathin scale.