Polarization-Mediated Modulation of Electronic and Transport Properties of Hybrid MoS-BaTiO-SrRuO Tunnel Junctions.

Hybrid structures composed of ferroelectric thin films and functional two-dimensional (2D) materials may exhibit unique characteristics and reveal new phenomena due to the cross-interface coupling between their intrinsic properties. In this report, we demonstrate a symbiotic interplay between spontaneous polarization of the ultrathin BaTiO ferroelectric film and conductivity of the adjacent molybdenum disulfide (MoS) layer, a 2D narrow-bandgap semiconductor. Polarization-induced modulation of the electronic properties of MoS results in a giant tunneling electroresistance effect in the hybrid MoS-BaTiO-SrRuO ferroelectric tunnel junctions (FTJs) with an OFF-to-ON resistance ratio as high as 10, a 50-fold increase in comparison with the same type of FTJs with metal electrodes. The effect stems from the reversible accumulation-depletion of the majority carriers in the MoS electrode in response to ferroelectric switching, which alters the barrier at the MoS-BaTiO interface. Continuous tunability of resistive states realized via stable sequential domain structures in BaTiO adds memristive functionality to the hybrid FTJs. The use of narrow band 2D semiconductors in conjunction with ferroelectric films provides a novel pathway for development of the electronic devices with enhanced performance.