Effect of a built-in electric field in asymmetric ferroelectric tunnel junctions

Abstract

The contribution of a built-in electric field to ferroelectric phase transition in asymmetric ferroelectric tunnel junctions is studied using a multiscale thermodynamic model. It is demonstrated in details that there exists a critical thickness at which an unusual ferroelectric-\'\' polar non-ferroelectric\rq\rq phase transition occurs in asymmetric ferroelectric tunnel junctions. In the \'\' polar non-ferroelectric\rq\rq phase, there is only one non-switchable polarization which is caused by the competition between the depolarizing field and the built-in field, and closure-like domains are proposed to form to minimize the system energy. The transition temperature is found to decrease monotonically as the ferroelectric barrier thickness is decreased and the reduction becomes more significant for the thinner ferroelectric layers. As a matter of fact, the built-in electric field does not only result in smearing of phase transition but also forces the transition to take place at a reduced temperature. Such findings may impose a fundamental limit on the work temperature and thus should be further taken into account in the future ferroelectric tunnel junction-type or ferroelectric capacitor-type devices.

9 pages, 8 figures, submitted to PRB

References in corpus (4)

• A ferroelectric memristor
• Theoretical current-voltage characteristics of ferroelectric tunnel junctions
• Unusual polarization patterns in flat epitaxial ferroelectric nanoparticles
• Depolarizing-Field Effect in Strained Nanoscale Ferroelectric Capacitors and Tunnel Junctions

Cited by in corpus (6)

• Physical Origin of Transient Negative Capacitance in a Ferroelectric Capacitor
• Theoretical Approach to Electroresistance in Ferroelectric Tunnel Junctions
• 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
• Ferroelectric tunnel junctions