The properties of ferroelectric materials, which were discovered almost a century ago1, have led to a huge range of applications, such as digital information storage2, pyroelectric energy conversion3 and neuromorphic computing4,5. Recently, it was shown that ferroelectrics can have negative capacitance6–11, which could improve the energy efficiency of conventional electronics beyond fundamental limits12–14. In Landau–Ginzburg–Devonshire theory15–17, this negative capacitance is directly related to the double-well shape of the ferroelectric polarization–energy landscape, which was thought for more than 70 years to be inaccessible to experiments18. Here we report electrical measurements of the intrinsic double-well energy landscape in a thin layer of ferroelectric Hf0.5Zr0.5O2. To achieve this, we integrated the ferroelectric into a heterostructure capacitor with a second dielectric layer to prevent immediate screening of polarization charges during switching. These results show that negative capacitance has its origin in the energy barrier in a double-well landscape. Furthermore, we demonstrate that ferroelectric negative capacitance can be fast and hysteresis-free, which is important for prospective applications19. In addition, the Hf0.5Zr0.5O2 used in this work is currently the most industry-relevant ferroelectric material, because both HfO2 and ZrO2 thin films are already used in everyday electronics20. This could lead to fast adoption of negative capacitance effects in future products with markedly improved energy efficiency.A ferroelectric thin film that behaves as a single domain is found to exhibit both negative capacitance and the predicted double-well polarization–energy relationship.

中文翻译：

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揭示铁电层中的双阱能量图谱

铁电材料的特性几乎在一个世纪前就被发现了，它带来了广泛的应用，例如数字信息存储 2、热释电能量转换 3 和神经形态计算 4、5。最近，表明铁电体可以具有负电容 6-11，这可以将传统电子产品的能源效率提高到超出基本限制 12-14。在 Landau-Ginzburg-Devonshire 理论 15-17 中，这种负电容与铁电极极化-能量景观的双阱形状直接相关，70 多年来，人们认为这种形状无法通过实验进行 18。在这里，我们报告了铁电 Hf0.5Zr0.5O2 薄层中本征双阱能量图谱的电学测量。为了达成这个，我们将铁电体集成到具有第二个介电层的异质结构电容器中，以防止在切换过程中立即屏蔽极化电荷。这些结果表明负电容起​​源于双阱景观中的能量势垒。此外，我们证明铁电负电容可以快速且无滞后，这对于预期应用很重要。此外，这项工作中使用的 Hf0.5Zr0.5O2 是目前与工业最相关的铁电材料，因为 HfO2 和 ZrO2 薄膜都已经用于日常电子产品20。这可能会导致在未来产品中快速采用负电容效应，并显着提高能源效率。