Modeling ferroelectric film properties and size effects from tetragonal interlayer in Hf1–xZrxO2 grains
Modeling ferroelectric film properties and size effects from tetragonal interlayer in Hf1–xZrxO2 grains
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DOI：
10.1063/1.4983811
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发表时间：
2017-05
影响因子：
3.2
通讯作者：
Christopher Künneth;Robin Materlik;A. Kersch
中科院分区：
文献类型：
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作者：
Christopher Künneth;Robin Materlik;A. Kersch
在最近发现的氧化锆-铪薄膜中，表面或界面能的尺寸效应在稳定铁电相方面起着关键作用。然而，由于掺杂剂的稳定作用的干扰，目前还缺乏足够的定量认识。对于一类重要的未掺杂Hf1-xZrxO2，基于密度泛函理论（DFT）的自由能和表面能值的相稳定性模型已经成功地描述了稀疏的实验和理论数据的关键性质。由于表面和界面容易受到干扰，该模型的预测能力令人惊讶，并指向迄今未被发现的潜在原因。新的实验数据提示在晶粒表面存在固定在四方相的中间层，可能屏蔽外界影响。为了探索这种机制的后果，我们建立了一个界面自由能模型，其中包括固定夹层。
Size effects from surface or interface energy play a pivotal role in stabilizing the ferroelectric phase in recently discovered thin film Zirconia-Hafnia. However, sufficient quantitative understanding has been lacking due to the interference with the stabilizing effect from dopants. For the important class of undoped Hf1–xZrxO2, a phase stability model based on free energy from Density functional theory (DFT) and surface energy values adapted to the sparse experimental and theoretical data has been successful to describe key properties of the available thin film data. Since surfaces and interfaces are prone to interference, the predictive capability of the model is surprising and directs to a hitherto undetected, underlying reason. New experimental data hint on the existence of an interlayer on the grain surface fixed in the tetragonal phase possibly shielding from external influence. To explore the consequences of such a mechanism, we develop an interface free energy model to include the fixed interlaye...