Polarization-Mediated Modulation of Electronic and Transport Properties of Hybrid MoS₂-BaTiO₃-SrRuO₃ 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 BaTiO₃ ferroelectric film and conductivity of the adjacent molybdenum disulfide (MoS₂) layer, a 2D narrow-bandgap semiconductor. Polarization-induced modulation of the electronic properties of MoS₂ results in a giant tunneling electroresistance effect in the hybrid MoS₂-BaTiO₃-SrRuO₃ ferroelectric tunnel junctions (FTJs) with an OFF-to-ON resistance ratio as high as 10⁴, 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 MoS₂ electrode in response to ferroelectric switching, which alters the barrier at the MoS₂-BaTiO₃ interface. Continuous tunability of resistive states realized via stable sequential domain structures in BaTiO₃ 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.