The giant tunneling electroresistance effect in monolayer In2SSeTe-based lateral ferroelectric tunnel junctions

Abstract

Two-dimensional (2D) asymmetric Janus materials display in-plane and out-of-plane intrinsic ferroelectricity due to their asymmetrical structures, which makes them suitable for ferroelectric data storage devices. Herein, by performing density functional calculations combined with nonequilibrium Green function simulations, we systematically study the ferroelectric properties of the 2D Janus In₂SSeTe monolayer and the electronic transport properties of the related ferroelectric tunnel junctions (FTJs) by employing graphene/germanene as the electrode. It is highlighted that both ferroelectric states of graphene/In₂SSeTe heterostructures show Ohmic contact, which is beneficial for decreasing the power dissipation of devices. Furthermore, the tunneling electroresistance (TER) ratios of the In₂SSeTe-based FTJs increase with the length of the devices. Interestingly, the FTJs of 9 nm central scattering region length with graphene/In₂SSeTe and germanene/In₂SSeTe electrodes can achieve maximum TER ratios of 2.24 × 10⁷% and 2.98 × 10⁸%, respectively. We believe that our findings will shed light on the design and application of the In₂SSeTe monolayer in FTJ devices.