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Electroresistance effect in ferroelectric tunnel junctions with symmetric electrodes
Daniel I Bilc1, Frederico D Novaes, Jorge Iñiguez
1Physique Théorique des Matériaux, Université de Liège, 4000 Liège, Belgium.
ACS Nano
|January 11, 2012
Summary
Large tunnel electroresistance (TER) effects in ferroelectric tunnel junctions (FTJs) are achievable with symmetric electrodes, challenging previous assumptions and paving the way for improved ferroelectric memory devices.
Area of Science:
- Condensed matter physics
- Materials science
- Nanotechnology
Background:
- Electronic transport in ferroelectric tunnel junctions (FTJs) is crucial for devices like ferroelectric memories.
- Current understanding is limited by semiempirical models and zero-bias first-principles calculations.
- Existing theories suggest differing electrodes are necessary for significant tunnel electroresistance (TER).
Purpose of the Study:
- To investigate the possibility of achieving large TER in FTJs with symmetric electrodes.
- To explore the underlying microscopic mechanisms governing TER.
- To critically evaluate existing theoretical models for FTJs.
Main Methods:
- First-principles calculations under finite bias.
- Atomistic simulations of ferroelectric tunnel junctions.
- Quantification of microscopic contributions to electroresistance.
Main Results:
- Demonstrated large TER values (~200%) in a prototypical FTJ with symmetric electrodes under finite bias.
- Identified the dominant role of the ferroelectric's inverse piezoelectric response in TER.
- Quantified contributions of various microscopic mechanisms to electroresistance.
Conclusions:
- Large TER is achievable in FTJs with symmetric electrodes, contrary to prevailing beliefs.
- The inverse piezoelectric effect significantly influences TER.
- First-principles calculations offer a more comprehensive understanding of FTJ electronic transport than traditional models.
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