Enhanced tunneling electroresistance effect in Pt/BiAlO3/Pt ferroelectric tunnel junctions by a graphene interlayer

Abstract

Realizing a large tunneling electroresistance (TER) effect with a low ON-state resistance-area product (RAP) is essential for the applications of ferroelectric tunnel junctions (FTJs) in information storage. Herein, taking Pt/BiAlO3/Pt (Pt/BAO/Pt) FTJs as examples, we theoretically demonstrate that a giant TER ratio of about 1458%, which is comparable to most van der Waals tunnel junctions, can be achieved by switching the electric polarization of ferroelectric BAO(0001) barrier due to the reversible metallization of ferroelectric in conjunction with the Schottky barrier. More interestingly, with the effective modulation on barrier height and width via polarization reversal, an enhanced TER effect close to 104% can be obtained by inserting a graphene monolayer into right (or left) Pt/BAO interface of the FTJs and the writing endurance of the FTJ memories is expected to be significantly improved. Furthermore, the calculated ON-state RAPs in all three FTJ devices are not more than 100 Ω μm2. These fascinating findings suggest that the proposed BAO-based FTJs hold great potential for designing next-generation nanoscale high-density and low-power nonvolatile memories with excellent performance.