Simulation of quantum dead-layers in nanoscale ferroelectric tunnel junctions

¹ Institute for Thin Films and Interfaces (ISG-1) and Center of Nanoelectronic Systems for Information Technology (CNI), Research Centre Jülich GmbH D-52425 Jülich, Germany
² Institute for Solid State Research (IFF) and Center of Nanoelectronic Systems for Information Technology (CNI), Research Centre Jülich GmbH D-52425 Jülich, Germany
³ Department of Material Science and Engineering and Department of Physics University of California - Berkeley, CA 94720, USA

Received: 30 March 2005
Accepted: 12 August 2005

Abstract

The usage of nanoscale ferroelectric films as tunnel barriers in electronic devices offers a unique possibility to study the physics of ultrathin ferroelectric materials by means of electronic transport. In this letter, we simulate the current-voltage characteristics of a metal-ferroelectric-metal tunnel junction by use of a nonequilibrium Green's function approach. We discuss the role of quantum effects such as Friedel oscillations, which lead to deviations from the conventional semiclassical description of contacts in such a tunneling structure. As a consequence, we predict a well-pronounced bistable resistive switching effect, depending on the polarization state of the ferroelectric tunnel barrier.