Pinned interface dipole-induced tunneling electroresistance in ferroelectric tunnel junctions

TL;DR

This study investigates how pinned interface dipoles influence tunneling electroresistance in ferroelectric tunnel junctions, revealing conditions for large TER and the effects of electrode choices.

Contribution

It introduces the concept of asymmetric interfaces with pinned and switchable dipoles in FTJs, analyzing their impact on TER using density functional theory.

Findings

Large TER achieved with pinned polarization pointing to ferroelectric film

TER is insensitive to the polarization variation of the pinned interface

Lower interface dielectric constants enhance TER

Abstract

Based on the structure predicted in a ferroelectric tunnel junction in the resent density functional theory study, we investigate the electron transport through the FTJ with asymmetric interfaces, i.e., one interface dipole is pinned and the other interface dipole is switchable. Tuneling electroresistance can be induced due to the nonswitchable interface dipole in FTJs with symmetric electrodes. Compared with the dependence relationship between TER and the polarization of switchable interface, TER is not sensitive to the variation of the polarization of pinned interface. A large TER can be achieved when the pinned polarization points to the ferroelectric film and low interface dielectric constants. In addition, effect of electrode on TER in the structure is also discussed.