Terahertz Reading of Ferroelectric Domain Wall Dielectric Switching.
Terahertz Reading of Ferroelectric Domain Wall Dielectric Switching.
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DOI：
10.1021/acsami.1c00523
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发表时间：
2021-03
影响因子：
9.5
通讯作者：
Man Zhang;Zhe Chen;Y. Yue;Tao Chen;Zhongna Yan;Q. Jiang;Bin Yang;M. Eriksson;Jianhua Tang-Jianhua
中科院分区：
文献类型：
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作者：
Man Zhang;Zhe Chen;Y. Yue;Tao Chen;Zhongna Yan;Q. Jiang;Bin Yang;M. Eriksson;Jianhua Tang-Jianhua
铁电畴壁（DW）是两个畴之间的重要纳米界面。铁电畴壁在太赫兹（THz）频率下无效地工作被广泛接受，因此阻碍了设计畴壁以创建利用THz辐射的新应用的努力。然而，本工作清楚地表明了无铅Aurivillius相铁电陶瓷Ca0.99Rb0.005Ce0.005Bi2Nb2O9中太赫兹频率下畴壁的活动，并使用太赫兹时域光谱（THz-TDS）进行了检查。在kHz和THz频率下，畴壁的动力学是不同的。在低频下，畴壁作为一个组工作以增加介电常数。在太赫兹频率下，畴壁的缺陷性质有助于降低整体介电常数。极化后THz波段的介电常数较高，反映了畴壁密度的降低，这证明了这一点。一个弹性振动模型也被用来验证一个单一的挫折偶极子在畴壁代表一个较弱的贡献比其对应的域内的介电常数。这项工作代表了理解太赫兹频率下畴壁介电贡献的根本突破。它还表明，太赫兹探测可以用来读取畴壁介电开关。
Ferroelectric domain walls (DWs) are important nanoscale interfaces between two domains. It is widely accepted that ferroelectric domain walls work idly at terahertz (THz) frequencies, consequently discouraging efforts to engineer the domain walls to create new applications that utilize THz radiation. However, the present work clearly demonstrates the activity of domain walls at THz frequencies in a lead-free Aurivillius phase ferroelectric ceramic, Ca0.99Rb0.005Ce0.005Bi2Nb2O9, examined using THz-time-domain spectroscopy (THz-TDS). The dynamics of domain walls are different at kHz and THz frequencies. At low frequencies, domain walls work as a group to increase dielectric permittivity. At THz frequencies, the defective nature of domain walls serves to lower the overall dielectric permittivity. This is evidenced by higher dielectric permittivity in the THz band after poling, reflecting decreased domain wall density. An elastic vibrational model has also been used to verify that a single frustrated dipole in a domain wall represents a weaker contribution to the permittivity than its counterpart within a domain. The work represents a fundamental breakthrough in understanding the dielectric contributions of domain walls at THz frequencies. It also demonstrates that THz probing can be used to read domain wall dielectric switching.