Theoretical current-voltage characteristics of ferroelectric tunnel junctions

By H. Kohlstedt, N. Pertsev, J. R. Contreras, R. W. I. F. Festkorperforschung, Cni, Forschungszentrum Juelich, Juelich, Heidelberg · Germany, A. P. Institute, R. A. O. Sciences and 5 more. 2005

346 citations recorded by the source corpus.

We present the concept of ferroelectric tunnel junctions (FTJs). These junctions consist of two metal electrodes separated by a nanometer-thick ferroelectric barrier. The current-voltage characteristics of FTJs are analyzed under the assumption that the direct electron tunneling represents the dominant conduction mechanism. First, the influence of converse piezoelectric effect inherent in ferroelectric materials on the tunnel current is described. The calculations show that the lattice strains of piezoelectric origin modify the current-voltage relationship owing to strain-induced changes of the barrier thickness, electron effective mass, and position of the conduction-band edge. Remarkably, the conductance minimum becomes shifted from zero voltage due to the piezoelectric effect, and a strain-related resistive switching takes place after the polarization reversal in a ferroelectric barrier. Second, we analyze the influence of the internal electric field arising due to imperfect screening of polarization charges by electrons in metal electrodes. It is shown that, for asymmetric FTJs, this depolarizing-field effect also leads to a considerable change of the barrier resistance after the polarization reversal. However, the symmetry of the resulting current-voltage loop is different from that characteristic of the strain-related resistive switching. The crossover from one to another type of the hysteretic curve, which accompanies the increase of FTJ asymmetry, is described taking into account both the strain and depolarizing-field effects. It is noted that asymmetric FTJs with dissimilar top and bottom electrodes are preferable for the non-volatile memory applications because of a larger resistance on/off ratio.

Subfields: Biomedical Engineering, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/4b577fc8662f2a293b203a030e34a7e9a52b3afd

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Citations in the corpus

Spintronics: A contemporary review of emerging electronics devices (2016, background): “There are at least 3 mechanisms reported, which produce TER effect [49].”
Tunnel junctions with multiferroic barriers. (2007, background): “and the influence of ferroelectricity on the tunnelling propertie”
Ferroelectric tunnel junctions for information storage and processing (2014, background): “Polarization charge effects induce an asymmetric modulation of the electronic potential proﬁle 10,11 .”