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The continued miniaturization of nanoelectronic devices approaches its fundamental physical limits due to power dissipation. Negative capacitance field-effect transistors using ferroelectric gate insulators are promising to overcome these limits, which would allow further device scaling. However, the microscopic details of negative capacitance are not well understood so far, since mainly Landau based mean-field theories are used to model these phenomena. Here we use an educational and simplified approach to better understand the basic microscopic origin of ferroelectric negative capacitance. Our “toy” model shows that negative capacitance originates from the thermodynamic instability of the ferroelectric polarization and is bounded by the saturation of microscopic dipole polarizability. This shows that negative capacitance is strongly connected to the origin of ferroelectricity itself. Furthermore, our microscopic model results in the same qualitative behavior as mean-field Landau based approaches.
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Ferroelectrics, Negative Capacitance and Depolarization Field: What exactly is negative capacitance?
2019 marks the 11 th year since the concept of ferroelectric negative capacitance was first proposed [1]. It was proposed as a physics solution to an engineering problem: The power dissipation in electronics and computing. Yet, it was unique in that the technology required a fundamental scientific discovery in a field that was ~90 years old at that time-the discovery of negative capacitance or static negative permittivity in ferroelectrics. Initially, interests into negative capacitance were limited to the device researchers; over time, the topic brought together the “often-disjoint” communities of device engineers, condensed matter physicists and material scientists in exploring, understanding and finally discovering this phenomenon [2]-[7]. Different manifestations of the negative capacitance phenomenon, namely, capacitance enhancement, negative differential relation between charge and voltage as well as atomic scale mapping of the stabilized, negative capacitance states corroborated with phase field and density functional theory based calculations have established this concept on a solid ground.
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- Award ID(s):
- 1718671
- PAR ID:
- 10391140
- Date Published:
- Journal Name:
- 2019 Device Research Conference (DRC)
- Page Range / eLocation ID:
- 57 to 58
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1109/DRC46940.2019.9046410
