Domain-Wall Tunneling Electroresistance Effect

Authors

M. Li, University of Nebraska-Lincoln
L. L. Tao, University of Nebraska-Lincoln
Evgeny Y. Tsymbal, University of Nebraska at LincolnFollow

Date of this Version

12-30-2019

Citation

PHYSICAL REVIEW LETTERS 123, 266602 (2019). DOI: 10.1103/PhysRevLett.123.266602

Comments

Used by permission.

Abstract

Ferroelectric tunnel junctions (FTJs) utilizing an in-plane head-to-head ferroelectric domain wall (DW) have recently been realized, showing interesting physics and new functionalities. However, the DW state in these junctions was found to be metastable and not reversible after applying an electric field. In this work, we demonstrate that a stable and reversible head-to-head DW state can be achieved in FTJs by proper engineering of polar interfaces. Using density functional theory (DFT) calculations and phenomenological modeling, we explore the DW stability by varying stoichiometry of the La_1−xSr_xO=TiO₂ interfaces in FTJs with La_0.5Sr_0.5MnO₃ electrodes and a ferroelectric BaTiO₃ tunnel barrier. For, x ≤ 0.4 we find that the DW state becomes a global minimum and the calculated hysteresis loops exhibit three reversible polarization states. For such FTJs, our quantum transport calculations predict the emergence of a DW tunneling electroresistance effect—reversible switching of the tunneling conductance between the highly conductive DW state and two much less conductive uniform polarization states.