Oxygen modulated quantum conductance for ultra-thin HfO$_2$-based memristive switching devices

TL;DR

This study models how oxygen atom movement within HfO₂ memristive devices affects quantum conductance, revealing high sensitivity and potential for precise control in resistive memory applications.

Contribution

The paper introduces a density functional theory model showing how oxygen atom positions modulate quantum conductance in HfO₂ memristive devices, highlighting the role of oxygen vacancies as tunneling barriers.

Findings

Conductance decreases exponentially with oxygen atom displacement.

Oxygen atom movement acts as a tunneling barrier within the filament.

Device conductance is highly sensitive to oxygen atom positions.

Abstract

Memristive switching devices, candidates for resistive random access memory technology, have been shown to switch off through a progression of states with quantized conductance and subsequent non-integer conductance (in terms of conductance quantum $G_0$). We have performed calculations based on density functional theory to model the switching process for a Pt-HfO$_2$-Pt structure, involving the movement of one or two oxygen atoms. Oxygen atoms moving within a conductive oxygen vacancy filament act as tunneling barriers, and partition the filament into weakly coupled quantum wells. We show that the low-bias conductance decreases exponentially when one oxygen atom moves away from interface. Our results demonstrate the high sensitivity of the device conductance to the position of oxygen atoms.