Giant Electroresistance in Ferroelectric Tunnel Junctions

TL;DR

This paper investigates how the polarization state of ultrathin ferroelectric barriers in metal/ferroelectric/metal junctions dramatically influences electron tunneling conductance, revealing a giant electroresistance effect.

Contribution

It introduces a model accounting for screening and quantum tunneling to explain large conductance changes due to polarization switching in ferroelectric tunnel junctions.

Findings

Conductance change of several orders of magnitude due to polarization reversal

Giant electroresistance effect linked to potential profile differences

Screening length differences significantly impact tunneling behavior

Abstract

The interplay between the electron transport in metal/ferroelectric/metal junctions with ultrathin ferroelectric barriers and the polarization state of a barrier is investigated. Using a model which takes into account screening of polarization charges in metallic electrodes and direct quantum tunneling across a ferroelectric barrier we calculate the change in the tunneling conductance associated with the polarization switching. We find the conductance change of a few orders of magnitude for metallic electrodes with significantly different screening lengths. This giant electroresistance effect is the consequence of a different potential profile seen by transport electrons for the two opposite polarization orientations.