Nanotube ferroelectric tunnel junctions with giant tunneling electroresistance ratio

TL;DR

This paper introduces a novel nanotube ferroelectric tunnel junction mechanism that leverages combined ferroelectric and flexoelectric polarization, achieving an ultrahigh tunneling electroresistance ratio for high-density nonvolatile memory devices.

Contribution

The work presents a new TER mechanism using ferroelectric nanotubes with combined polarization effects, demonstrated through first-principles calculations, achieving an ultrahigh TER ratio.

Findings

Ultrahigh TER ratio exceeding 9.9×10^10% demonstrated.

Feasibility confirmed using { extalpha}-In2Se3 as an example.

Tunable conducting states via axial electric field.

Abstract

Low-dimensional ferroelectric tunnel junctions are appealing for the realization of nanoscale nonvolatile memory devices due to their inherent advantage of device miniaturization. Those based on current mechanisms still have restrictions including low tunneling electroresistance (TER) effects and complex heterostructures. Here, we introduce an entirely new TER mechanism to construct the nanotube ferroelectric tunnel junction with ferroelectric nanotubes as the tunneling region. When rolling a ferroelectric monolayer into a nanotube, due to the coexistence of its intrinsic ferroelectric polarization with the flexoelectric polarization induced by bending, there occurs metal-insulator transition depending on radiative polarization states. For the pristine monolayer, its out-of-plane polarization is tunable by an in-plane electric field, the conducting states of the ferroelectric nanotube can thus be tuned between metallic and insulating via axial electric means. Using {\alpha}-In2Se3 as an example, our first-principles density functional theory calculations and nonequilibrium Green's function formalism confirm the feasibility of the TER mechanism and indicate an ultrahigh TER ratio exceeding 9.9*10^10% of the proposed nanotube ferroelectric tunnel junctions. Our findings provide a promising approach based on simple homogeneous structures for high density ferroelectric microelectronic devices with excellent ON/OFF performance.