文章基本信息

标题：Frustration of Negative Capacitance in Al₂O₃/BaTiO₃ Bilayer Structure
本地全文：下载
作者：Yu Jin Kim ; Min Hyuk Park ; Young Hwan Lee 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2016
卷号：6
DOI：10.1038/srep19039
出版社：Springer Nature
摘要：Enhancement of capacitance by negative capacitance (NC) effect in a dielectric/ferroelectric (DE/FE) stacked film is gaining a greater interest. While the previous theory on NC effect was based on the Landau-Ginzburg-Devonshire theory, this work adopted a modified formalism to incorporate the depolarization effect to describe the energy of the general DE/FE system. The model predicted that the SrTiO₃/BaTiO₃ system will show a capacitance boost effect. It was also predicted that the 5 nm-thick Al₂O₃/150 nm-thick BaTiO₃ system shows the capacitance boost effect with no FE-like hysteresis behavior, which was inconsistent with the experimental results; the amorphous-Al₂O₃/epitaxial-BaTiO₃ system showed a typical FE-like hysteresis loop in the polarization – voltage test. This was due to the involvement of the trapped charges at the DE/FE interface, originating from the very high field across the thin Al₂O₃ layer when the BaTiO₃ layer played a role as the NC layer. Therefore, the NC effect in the Al₂O₃/BaTiO₃ system was frustrated by the involvement of reversible interface charge; the highly stored charge by the NC effect of the BaTiO₃ during the charging period could not be retrieved during the discharging process because integral part of the polarization charge was retained within the system as a remanent polarization.