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.

12 pages

References in corpus (3)

• Theoretical current-voltage characteristics of ferroelectric tunnel junctions
• Ferroelectricity in ultra-thin perovskite films
• Electroresistance effects in ferroelectric tunnel barriers

Cited by in corpus (3)

• Physical Origin of Transient Negative Capacitance in a Ferroelectric 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