Domain wall-localized phonons in BiFeO3: spectrum and selection rules
Domain wall-localized phonons in BiFeO3: spectrum and selection rules
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DOI：
10.1038/s41524-020-0304-y
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发表时间：
2020-05
影响因子：
9.7
通讯作者：
Peng Chen;Louis Ponet;K. Lai;R. Cingolani;S. Artyukhin
中科院分区：
文献类型：
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作者：
Peng Chen;Louis Ponet;K. Lai;R. Cingolani;S. Artyukhin
铁电畴壁（DWs）是纳米级的拓扑缺陷，可以很容易地定制以创建纳米级器件。他们的激发，最近被发现是GHz DW电导率的原因，与现有技术相比，有望实现更快的信号传输和处理。在这里，我们发现DW声子具有前所未有的色散，从GHz一直到太赫兹频率，并导致DW电导率具有惊人的宽GHz特征。在bifeo3中，名义上被禁止的DW滑动模式的令人困惑的激活可以追溯到DW倾斜和由此导致的壁定域声子的不对称。所获得的声子谱和选择规则被用于模拟扫描阻抗显微镜，成为纳米声子学中一个强大的探针。研究结果将指导声子分支的实验发现，以及在技术上重要的频率范围内设计基于dw的纳米器件。
Ferroelectric domain walls (DWs) are nanoscale topological defects that can be easily tailored to create nanoscale devices. Their excitations, recently discovered to be responsible for GHz DW conductivity, hold promise for faster signal transmission and processing compared to the existing technology. Here we find that DW phonons have unprecedented dispersion going from GHz all the way to THz frequencies, and resulting in a surprisingly broad GHz signature in DW conductivity. Puzzling activation of nominally forbidden DW sliding modes in BiFeO3is traced back to DW tilting and resulting asymmetry in wall-localized phonons. The obtained phonon spectra and selection rules are used to simulate scanning impedance microscopy, emerging as a powerful probe in nanophononics. The results will guide the experimental discovery of the predicted phonon branches and design of DW-based nanodevices operating in the technologically important frequency range.