arXivDaily arXiv每日学术速递 周一至周五更新
北美退伍军人节(Veterans Day),12 日无更新
arXiv 1902.01022cond-mat.mtrl-sci
收藏

硅基ZrO $_{2}$铁电单层膜理论

Theory of Ferroelectric ZrO$_{2}$ Monolayers on Si

Mehmet Dogan, Sohrab Ismail-Beigi

摘要:

我们用密度泛函理论和Monte Carlo晶格模拟方法研究了Si(001)衬底上ZrO $_{2}$单分子膜的结构。最近,我们报道了在硅衬底上生长非晶ZrO $_{2}$单层膜及其铁电性能,标志着最薄铁电氧化物的成功[M. Dogan等人,Nano Lett.,18(1)(2018)]。在这里,我们首先描述了丰富的景观的单晶ZrO $_{2}$单分子膜的原子配置在Si上,并确定当地的能量最小值。由于我们发现的低能量配置的众多,我们认为不同配置的有限大小的区域的共存。我们创建了一个简单的最近邻晶格模型,从DFT计算中提取的参数,并使用簇蒙特卡罗算法数值求解。我们的研究结果表明,在室温下,ZrO $_{2}$单层由两个低能量配置的小畴相反的铁电极化。这解释了在实验膜中观察到的铁电行为,作为晶体区域的集合,其尺寸为几纳米,随着外部电场的施加而切换。

英文摘要:

We use density functional theory and Monte Carlo lattice simulations to investigate the structure of ZrO$_{2}$ monolayers on Si(001). Recently, we have reported on the experimental growth of amorphous ZrO$_{2}$ monolayers on silicon and their ferroelectric properties, marking the achievement of the thinnest possible ferroelectric oxide [M. Dogan et al. Nano Lett., 18 (1) (2018)]. Here, we first describe the rich landscape of atomic configurations of monocrystalline ZrO$_{2}$ monolayers on Si and determine the local energy minima. Because of the multitude of low-energy configurations we find, we consider the coexistence of finite-sized regions of different configurations. We create a simple nearest-neighbor lattice model with parameters extracted from DFT calculations, and solve it numerically using a cluster Monte Carlo algorithm. Our results suggest that up to room temperature, the ZrO$_{2}$ monolayer consists of small domains of two low-energy configurations with opposite ferroelectric polarization. This explains the observed ferroelectric behavior in the experimental films as a collection of crystalline regions, which are a few nanometers in size, being switched with the application of an external electric field.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑