Polarization-controlled Ohmic to Schottky transition at a metal/ferroelectric interface

Authors

Xiaohui Liu, University of Nebraska-LincolnFollow
Yong Wang, Pacific Northwest National Laboratory
John D. Burton, University of Nebraska - LincolnFollow
Evgeny Y. Tsymbal, University of Nebraska-LincolnFollow

Date of this Version

10-30-2013

Citation

PHYSICAL REVIEW B 88, 165139 (2013). DOI: 10.1103/PhysRevB.88.165139

Comments

Copyright (c) 2013 American Physical Society. Used by permission.

Abstract

Ferroelectric polar displacements have recently been observed in conducting electron-doped BaTiO₃ (n-BTO). The coexistence of a ferroelectric phase and conductivity opens the door to new functionalities that may provide a unique route for novel device applications. Using first-principles methods and electrostatic modeling, we explore the effect that the switchable polarization of n-BTO has on the electronic properties of the SrRuO₃/n-BTO (001) interface. Ferroelectric polarization controls the accumulation or depletion of electron charge at the interface, and the associated bending of the n-BTO conduction band determines the transport regime across the interface. The interface exhibits a Schottky tunnel barrier for one polarization orientation, whereas an Ohmic contact is present for the opposite polarization orientation, leading to a large change in interface resistance associated with polarization reversal. Our calculations reveal a five orders of magnitude change in the interface resistance because of polarization switching.