Theoretical Approach to Electroresistance in Ferroelectric Tunnel Junctions

Abstract

In this paper, a theoretical approach, comprising the non-equilibrium Green's function method for electronic transport and Landau-Khalatnikov equation for electric polarization dynamics, is presented to describe polarization-dependent tunneling electroresistance (TER) in ferroelectric tunnel junctions. Using appropriate contact, interface, and ferroelectric parameters, measured current-voltage characteristic curves in both inorganic (Co/BaTiO${}_3$/La${}_{0.67}$Sr${}_{0.33}$MnO${}_3$) and organic (Au/PVDF/W) ferroelectric tunnel junctions can be well described by the proposed approach. Furthermore, under this theoretical framework, the controversy of opposite TER signs observed experimentally by different groups in Co/BaTiO${}_3$/La${}_{0.67}$Sr${}_{0.33}$MnO${}_3$ systems is addressed by considering the interface termination effects using the effective contact ratio, defined through the effective screening length and dielectric response at the metal/ferroelectric interfaces. Finally, our approach is extended to investigate the role of a CoO${}_x$ buffer layer at the Co/BaTiO${}_3$ interface in a ferroelectric tunnel memristor. It is shown that, to have a significant memristor behavior, not only the interface oxygen vacancies but also the CoO${}_x$ layer thickness may vary with the applied bias.

arXiv comment12 pages

References in corpus (8)

• Giant Electroresistance in Ferroelectric Tunnel Junctions
• Tunneling electroresistance effect in ferroelectric tunnel junctions at the nanoscale
• Enhancement of ferroelectricity at metal/oxide interfaces
• Theoretical current-voltage characteristics of ferroelectric tunnel junctions
• Ferroelectricity in ultra-thin perovskite films
• Electroresistance effects in ferroelectric tunnel barriers
• Tunneling Electroresistance in Ferroelectric Tunnel Junctions with a Composite Barrier
• Effect of a built-in electric field in asymmetric ferroelectric tunnel junctions

Cited by in corpus (5)

• Physical Origin of Transient Negative Capacitance in a Ferroelectric Capacitor
• A Thermodynamic Perspective of Negative-capacitance Field-effect-transistors
• Inversion Charge-boost and Transient Steep-slope induced by Free charge-polarization Mismatch in a Ferroelectric-metal-oxide-semiconductor Capacitor
• Non-equilibrium Green's Function and First Principle Approach to Modeling of Multiferroic Tunnel Junctions
• Insights into electron transport in a ferroelectric tunnel junction